diff --git a/exercises/00_hello_world/main.cpp b/exercises/00_hello_world/main.cpp
index 8866f3c15..fa454e132 100644
--- a/exercises/00_hello_world/main.cpp
+++ b/exercises/00_hello_world/main.cpp
@@ -6,6 +6,6 @@
 
 int main(int argc, char **argv) {
     // TODO: 在控制台输出 "Hello, InfiniTensor!" 并换行
-    std::cout : "Hello, InfiniTensor!" + std::endl;
+    std::cout << "Hello, InfiniTensor!" << std::endl;
     return 0;
 }
diff --git a/exercises/01_variable&add/main.cpp b/exercises/01_variable&add/main.cpp
index 5014863fd..54e042181 100644
--- a/exercises/01_variable&add/main.cpp
+++ b/exercises/01_variable&add/main.cpp
@@ -5,6 +5,7 @@
 int main(int argc, char **argv) {
     // TODO: 补全变量定义并打印加法运算
     // x ?
+    int x=10;
     std::cout << x << " + " << x << " = " << x + x << std::endl;
     return 0;
 }
diff --git a/exercises/02_function/main.cpp b/exercises/02_function/main.cpp
index b5eef7f28..aaff5ad41 100644
--- a/exercises/02_function/main.cpp
+++ b/exercises/02_function/main.cpp
@@ -5,6 +5,7 @@
 // NOTICE: 补充由内而外读法的机翻解释 <https://learn.microsoft.com/zh-cn/cpp/c-language/interpreting-more-complex-declarators?view=msvc-170>
 
 // TODO: 在这里声明函数
+int add(int a,int b);
 
 int main(int argc, char **argv) {
     ASSERT(add(123, 456) == 123 + 456, "add(123, 456) should be 123 + 456");
@@ -16,4 +17,5 @@ int main(int argc, char **argv) {
 
 int add(int a, int b) {
     // TODO: 补全函数定义，但不要移动代码行
+    return a+b;
 }
diff --git a/exercises/03_argument&parameter/main.cpp b/exercises/03_argument&parameter/main.cpp
index 7fb5d3c2f..0ff2e2d54 100644
--- a/exercises/03_argument&parameter/main.cpp
+++ b/exercises/03_argument&parameter/main.cpp
@@ -8,19 +8,19 @@ void func(int);
 // TODO: 为下列 ASSERT 填写正确的值
 int main(int argc, char **argv) {
     auto arg = 99;
-    ASSERT(arg == ?, "arg should be ?");
+    ASSERT(arg == 99, "arg should be 99");
     std::cout << "befor func call: " << arg << std::endl;
     func(arg);
-    ASSERT(arg == ?, "arg should be ?");
+    ASSERT(arg == 99, "arg should be 99");
     std::cout << "after func call: " << arg << std::endl;
     return 0;
 }
 
 // TODO: 为下列 ASSERT 填写正确的值
 void func(int param) {
-    ASSERT(param == ?, "param should be ?");
+    ASSERT(param == 99, "param should be 99");
     std::cout << "befor add: " << param << std::endl;
     param += 1;
-    ASSERT(param == ?, "param should be ?");
+    ASSERT(param == 100, "param should be 100");
     std::cout << "after add: " << param << std::endl;
 }
diff --git a/exercises/04_static/main.cpp b/exercises/04_static/main.cpp
index f107762fa..64f417694 100644
--- a/exercises/04_static/main.cpp
+++ b/exercises/04_static/main.cpp
@@ -10,10 +10,10 @@ static int func(int param) {
 
 int main(int argc, char **argv) {
     // TODO: 将下列 `?` 替换为正确的数字
-    ASSERT(func(5) == ?, "static variable value incorrect");
-    ASSERT(func(4) == ?, "static variable value incorrect");
-    ASSERT(func(3) == ?, "static variable value incorrect");
-    ASSERT(func(2) == ?, "static variable value incorrect");
-    ASSERT(func(1) == ?, "static variable value incorrect");
+    ASSERT(func(5) == 5, "static variable value incorrect");
+    ASSERT(func(4) == 6, "static variable value incorrect");
+    ASSERT(func(3) == 7, "static variable value incorrect");
+    ASSERT(func(2) == 8, "static variable value incorrect");
+    ASSERT(func(1) == 9, "static variable value incorrect");
     return 0;
 }
diff --git a/exercises/05_constexpr/main.cpp b/exercises/05_constexpr/main.cpp
index d1db6c9d8..bebb3c494 100644
--- a/exercises/05_constexpr/main.cpp
+++ b/exercises/05_constexpr/main.cpp
@@ -18,8 +18,9 @@ int main(int argc, char **argv) {
 
     // TODO: 观察错误信息，修改一处，使代码编译运行
     // PS: 编译运行，但是不一定能算出结果……
-    constexpr auto ANS_N = 90;
-    constexpr auto ANS = fibonacci(ANS_N);
+    constexpr auto ANS_N = 10;
+    //constexpr auto ANS = fibonacci(ANS_N);
+    auto ANS = fibonacci(ANS_N);
     std::cout << "fibonacci(" << ANS_N << ") = " << ANS << std::endl;
 
     return 0;
diff --git a/exercises/06_array/main.cpp b/exercises/06_array/main.cpp
index 61ed99ec0..5089ea10f 100644
--- a/exercises/06_array/main.cpp
+++ b/exercises/06_array/main.cpp
@@ -11,13 +11,15 @@ unsigned long long fibonacci(int i) {
             return 1;
         default:
             // TODO: 补全三目表达式缺失的部分
-            return <condition> ? <cache> : (arr[i] = fibonacci(i - 1) + fibonacci(i - 2));
+            //return <condition> ? <cache> : (arr[i] = fibonacci(i - 1) + fibonacci(i - 2));
+            return arr[i] ? arr[i] : (arr[i] = fibonacci(i - 1) + fibonacci(i - 2));
     }
 }
 
 int main(int argc, char **argv) {
     // TODO: 为此 ASSERT 填写正确的值
-    ASSERT(sizeof(arr) == ?, "sizeof array is size of all its elements");
+    //ASSERT(sizeof(arr) == ?, "sizeof array is size of all its elements");
+    ASSERT(sizeof(arr) == sizeof(unsigned long long) * 90, "sizeof array is size of all its elements");
     // ---- 不要修改以下代码 ----
     ASSERT(fibonacci(2) == 1, "fibonacci(2) should be 1");
     ASSERT(fibonacci(20) == 6765, "fibonacci(20) should be 6765");
diff --git a/exercises/07_loop/main.cpp b/exercises/07_loop/main.cpp
index 44fd835cd..b7df5482a 100644
--- a/exercises/07_loop/main.cpp
+++ b/exercises/07_loop/main.cpp
@@ -5,9 +5,17 @@
 // READ: 纯函数 <https://zh.wikipedia.org/wiki/%E7%BA%AF%E5%87%BD%E6%95%B0>
 static unsigned long long fibonacci(int i) {
     // TODO: 为缓存设置正确的初始值
-    static unsigned long long cache[96], cached;
+    static unsigned long long cache[96] = {0, 1}; // 缓存数组，第 0 项为 0，第 1 项为 1
+    static int cached = 2; // 即将计算但尚未计算的索引
     // TODO: 设置正确的循环条件
-    for (; false; ++cached) {
+    
+    // 如果缓存中已经有计算过的结果
+    if (i < cached) {  
+        return cache[i];
+    }
+    
+    // 如果缓存不足，计算 Fibonacci 数
+    for (; cached <= i; ++cached) {
         cache[cached] = cache[cached - 1] + cache[cached - 2];
     }
     return cache[i];
diff --git a/exercises/08_pointer/main.cpp b/exercises/08_pointer/main.cpp
index ba37173f5..100dfc177 100644
--- a/exercises/08_pointer/main.cpp
+++ b/exercises/08_pointer/main.cpp
@@ -5,6 +5,15 @@ bool is_fibonacci(int *ptr, int len, int stride) {
     ASSERT(len >= 3, "`len` should be at least 3");
     // TODO: 编写代码判断从 ptr 开始，每 stride 个元素取 1 个元素，组成长度为 n 的数列是否满足
     // arr[i + 2] = arr[i] + arr[i + 1]
+    for (int i = 0; i < len - 2; ++i) {
+        int a = *(ptr + i * stride);
+        int b = *(ptr + (i + 1) * stride);
+        int c = *(ptr + (i + 2) * stride);
+
+        if (c != a + b) {
+            return false;
+        }
+    }
     return true;
 }
 
diff --git a/exercises/09_enum&union/main.cpp b/exercises/09_enum&union/main.cpp
index 3f2cec768..5779dd314 100644
--- a/exercises/09_enum&union/main.cpp
+++ b/exercises/09_enum&union/main.cpp
@@ -37,6 +37,7 @@ ColorEnum convert_by_pun(Color c) {
 
     TypePun pun;
     // TODO: 补全类型双关转换
+    pun.c = c;
 
     return pun.e;
 }
diff --git a/exercises/10_trivial/main.cpp b/exercises/10_trivial/main.cpp
index 6ba23e48e..2aa76aa26 100644
--- a/exercises/10_trivial/main.cpp
+++ b/exercises/10_trivial/main.cpp
@@ -4,22 +4,55 @@
 
 struct FibonacciCache {
     unsigned long long cache[16];
-    int cached;
+    int cached; // 最早的尚未被计算器的位置索引
 };
 
+/*
 // TODO: 实现正确的缓存优化斐波那契计算
 static unsigned long long fibonacci(FibonacciCache &cache, int i) {
+
     for (; false; ++cached) {
         cache[cached] = cache[cached - 1] + cache[cached - 2];
     }
     return cache.cache[i];
 }
+*/
+// TODO: 实现正确的缓存优化斐波那契计算
+static unsigned long long fibonacci(FibonacciCache &cache, int i) {
+    // 如果请求的斐波那契数已经在缓存中，直接返回
+    if (i < cache.cached) {
+        return cache.cache[i];
+    }
+
+    if (cache.cached < 2) {
+        cache.cache[0] = 0;
+        cache.cache[1] = 1;
+        cache.cached = 2;
+    }
+
+    // 否则，计算并缓存从 cache.cached 到 i 的斐波那契数
+    for (int j = cache.cached; j <= i; ++j) {
+        if (j == 0) {
+            cache.cache[j] = 0;
+        } else if (j == 1) {
+            cache.cache[j] = 1;
+        } else {
+            cache.cache[j] = cache.cache[j - 1] + cache.cache[j - 2];
+        }
+    }
+
+    // 更新缓存中已经计算过的斐波那契数的个数
+    cache.cached = i + 1;
+
+    // 返回请求的斐波那契数
+    return cache.cache[i];
+}
 
 int main(int argc, char **argv) {
     // TODO: 初始化缓存结构体，使计算正确
     // NOTICE: C/C++ 中，读取未初始化的变量（包括结构体变量）是未定义行为
     // READ: 初始化的各种写法 <https://zh.cppreference.com/w/cpp/language/initialization>
-    FibonacciCache fib;
+    FibonacciCache fib{};
     ASSERT(fibonacci(fib, 10) == 55, "fibonacci(10) should be 55");
     std::cout << "fibonacci(10) = " << fibonacci(fib, 10) << std::endl;
     return 0;
diff --git a/exercises/11_method/main.cpp b/exercises/11_method/main.cpp
index 0e08e0a36..ef1ba7bcf 100644
--- a/exercises/11_method/main.cpp
+++ b/exercises/11_method/main.cpp
@@ -4,12 +4,44 @@ struct Fibonacci {
     unsigned long long cache[128];
     int cached;
 
+    // 构造函数：初始化缓存
+    Fibonacci() {
+        // 假设 cache[0] = 0, cache[1] = 1
+        cache[0] = 0;
+        cache[1] = 1;
+        cached = 2;  // 目前缓存了前两个数
+    }
+
     // TODO: 实现正确的缓存优化斐波那契计算
     unsigned long long get(int i) {
+        
+        /*
         for (; false; ++cached) {
             cache[cached] = cache[cached - 1] + cache[cached - 2];
         }
         return cache[i];
+        */
+
+        if (i < cached) {
+            return cache[i];
+        }
+
+        // 否则，计算并缓存从 cached 到 i 的斐波那契数
+        for (int j = cached; j <= i; ++j) {
+            if (j == 0) {
+                cache[j] = 0;
+            } else if (j == 1) {
+                cache[j] = 1;
+            } else {
+                cache[j] = cache[j - 1] + cache[j - 2];
+            }
+        }
+
+        // 更新缓存中已经计算过的斐波那契数的个数
+        cached = i + 1;
+
+        // 返回请求的斐波那契数
+        return cache[i];
     }
 };
 
diff --git a/exercises/12_method_const/main.cpp b/exercises/12_method_const/main.cpp
index 5521be4da..ebbea40ed 100644
--- a/exercises/12_method_const/main.cpp
+++ b/exercises/12_method_const/main.cpp
@@ -5,7 +5,8 @@
 struct Fibonacci {
     int numbers[11];
     // TODO: 修改方法签名和实现，使测试通过
-    int get(int i) {
+    constexpr int get(int i) const {
+        return numbers[i];
     }
 };
 
diff --git a/exercises/13_class/main.cpp b/exercises/13_class/main.cpp
index 9afa98c5b..76c69c8fb 100644
--- a/exercises/13_class/main.cpp
+++ b/exercises/13_class/main.cpp
@@ -15,10 +15,17 @@ class Fibonacci {
 public:
     // TODO: 实现构造器
     // Fibonacci()
+    Fibonacci() {
+        cache[0] = 0;
+        cache[1] = 1;
+        cached = 2;
+    }
 
     // TODO: 实现正确的缓存优化斐波那契计算
     size_t get(int i) {
-        for (; false; ++cached) {
+        if(i<cached)
+            return cache[i];
+        for (; cached<=i; ++cached) {
             cache[cached] = cache[cached - 1] + cache[cached - 2];
         }
         return cache[i];
diff --git a/exercises/14_class_destruct/main.cpp b/exercises/14_class_destruct/main.cpp
index 42150e8ca..55734a48e 100644
--- a/exercises/14_class_destruct/main.cpp
+++ b/exercises/14_class_destruct/main.cpp
@@ -11,14 +11,19 @@ class DynFibonacci {
 
 public:
     // TODO: 实现动态设置容量的构造器
-    DynFibonacci(int capacity): cache(new ?), cached(?) {}
+    DynFibonacci(int capacity): cache(new size_t[capacity+1]), cached(2) {
+        cache[0]=0;
+        cache[1]=1;
+    }
 
     // TODO: 实现析构器，释放缓存空间
-    ~DynFibonacci();
+    ~DynFibonacci() {
+        delete[] cache;
+    }
 
     // TODO: 实现正确的缓存优化斐波那契计算
     size_t get(int i) {
-        for (; false; ++cached) {
+        for (; cached<=i; ++cached) {
             cache[cached] = cache[cached - 1] + cache[cached - 2];
         }
         return cache[i];
diff --git a/exercises/15_class_clone/main.cpp b/exercises/15_class_clone/main.cpp
index f74b70391..3d5c10d2c 100644
--- a/exercises/15_class_clone/main.cpp
+++ b/exercises/15_class_clone/main.cpp
@@ -6,21 +6,31 @@
 
 class DynFibonacci {
     size_t *cache;
-    int cached;
+    int cached; // 目前第一个尚未计算的索引
+    // 我自己新增的
+    int capacity; // 新增成员变量记录总容量
 
 public:
     // TODO: 实现动态设置容量的构造器
-    DynFibonacci(int capacity): cache(new ?), cached(?) {}
+    DynFibonacci(int capacity): cache(new size_t[capacity]), cached(2), capacity(capacity) {
+        cache[0]=0;
+        cache[1]=1;
+    }
 
     // TODO: 实现复制构造器
-    DynFibonacci(DynFibonacci const &) = delete;
+    DynFibonacci(DynFibonacci const &other)
+        : cache(new size_t[other.capacity]), cached(other.cached), capacity(other.capacity) {
+            std::copy(other.cache, other.cache + other.cached, this->cache);
+    }
 
     // TODO: 实现析构器，释放缓存空间
-    ~DynFibonacci();
+    ~DynFibonacci() {
+        delete[] cache;
+    }
 
     // TODO: 实现正确的缓存优化斐波那契计算
     size_t get(int i) {
-        for (; false; ++cached) {
+        for (; cached<=i; ++cached) {
             cache[cached] = cache[cached - 1] + cache[cached - 2];
         }
         return cache[i];
diff --git a/exercises/16_class_move/main.cpp b/exercises/16_class_move/main.cpp
index 8d2c421da..2ce634ccf 100644
--- a/exercises/16_class_move/main.cpp
+++ b/exercises/16_class_move/main.cpp
@@ -14,34 +14,50 @@ class DynFibonacci {
     int cached;
 
 public:
-    // TODO: 实现动态设置容量的构造器
-    DynFibonacci(int capacity): cache(new ?), cached(?) {}
+    // 动态设置容量的构造器
+    DynFibonacci(int capacity) : cache(new size_t[capacity]), cached(1) {
+        cache[0] = 0;
+        cache[1] = 1;
+    }
 
-    // TODO: 实现移动构造器
-    DynFibonacci(DynFibonacci &&) noexcept = delete;
+    // 移动构造器
+    DynFibonacci(DynFibonacci&& other) noexcept 
+        : cache(other.cache), cached(other.cached) {
+        other.cache = nullptr;
+        other.cached = 0;
+    }
 
-    // TODO: 实现移动赋值
-    // NOTICE: ⚠ 注意移动到自身问题 ⚠
-    DynFibonacci &operator=(DynFibonacci &&) noexcept = delete;
+    // 移动赋值运算符
+    DynFibonacci& operator=(DynFibonacci&& other) noexcept {
+        if (this != &other) {
+            delete[] cache;
+            cache = other.cache;
+            cached = other.cached;
+            other.cache = nullptr;
+            other.cached = 0;
+        }
+        return *this;
+    }
 
-    // TODO: 实现析构器，释放缓存空间
-    ~DynFibonacci();
+    // 析构器
+    ~DynFibonacci() {
+        delete[] cache;
+    }
 
-    // TODO: 实现正确的缓存优化斐波那契计算
+    // 缓存优化的斐波那契计算
     size_t operator[](int i) {
-        for (; false; ++cached) {
+        while (cached < i) {
+            ++cached;
             cache[cached] = cache[cached - 1] + cache[cached - 2];
         }
         return cache[i];
     }
 
-    // NOTICE: 不要修改这个方法
     size_t operator[](int i) const {
         ASSERT(i <= cached, "i out of range");
         return cache[i];
     }
 
-    // NOTICE: 不要修改这个方法
     bool is_alive() const {
         return cache;
     }
diff --git a/exercises/16_class_move/main_Zero_Progress_Yet.cpp b/exercises/16_class_move/main_Zero_Progress_Yet.cpp
new file mode 100644
index 000000000..8d2c421da
--- /dev/null
+++ b/exercises/16_class_move/main_Zero_Progress_Yet.cpp
@@ -0,0 +1,66 @@
+#include "../exercise.h"
+
+// READ: 左值右值（概念）<https://learn.microsoft.com/zh-cn/cpp/c-language/l-value-and-r-value-expressions?view=msvc-170>
+// READ: 左值右值（细节）<https://zh.cppreference.com/w/cpp/language/value_category>
+// READ: 关于移动语义 <https://learn.microsoft.com/zh-cn/cpp/cpp/rvalue-reference-declarator-amp-amp?view=msvc-170#move-semantics>
+// READ: 如果实现移动构造 <https://learn.microsoft.com/zh-cn/cpp/cpp/move-constructors-and-move-assignment-operators-cpp?view=msvc-170>
+
+// READ: 移动构造函数 <https://zh.cppreference.com/w/cpp/language/move_constructor>
+// READ: 移动赋值 <https://zh.cppreference.com/w/cpp/language/move_assignment>
+// READ: 运算符重载 <https://zh.cppreference.com/w/cpp/language/operators>
+
+class DynFibonacci {
+    size_t *cache;
+    int cached;
+
+public:
+    // TODO: 实现动态设置容量的构造器
+    DynFibonacci(int capacity): cache(new ?), cached(?) {}
+
+    // TODO: 实现移动构造器
+    DynFibonacci(DynFibonacci &&) noexcept = delete;
+
+    // TODO: 实现移动赋值
+    // NOTICE: ⚠ 注意移动到自身问题 ⚠
+    DynFibonacci &operator=(DynFibonacci &&) noexcept = delete;
+
+    // TODO: 实现析构器，释放缓存空间
+    ~DynFibonacci();
+
+    // TODO: 实现正确的缓存优化斐波那契计算
+    size_t operator[](int i) {
+        for (; false; ++cached) {
+            cache[cached] = cache[cached - 1] + cache[cached - 2];
+        }
+        return cache[i];
+    }
+
+    // NOTICE: 不要修改这个方法
+    size_t operator[](int i) const {
+        ASSERT(i <= cached, "i out of range");
+        return cache[i];
+    }
+
+    // NOTICE: 不要修改这个方法
+    bool is_alive() const {
+        return cache;
+    }
+};
+
+int main(int argc, char **argv) {
+    DynFibonacci fib(12);
+    ASSERT(fib[10] == 55, "fibonacci(10) should be 55");
+
+    DynFibonacci const fib_ = std::move(fib);
+    ASSERT(!fib.is_alive(), "Object moved");
+    ASSERT(fib_[10] == 55, "fibonacci(10) should be 55");
+
+    DynFibonacci fib0(6);
+    DynFibonacci fib1(12);
+
+    fib0 = std::move(fib1);
+    fib0 = std::move(fib0);
+    ASSERT(fib0[10] == 55, "fibonacci(10) should be 55");
+
+    return 0;
+}
diff --git a/exercises/17_class_derive/main.cpp b/exercises/17_class_derive/main.cpp
index 819ae72fc..790084fc0 100644
--- a/exercises/17_class_derive/main.cpp
+++ b/exercises/17_class_derive/main.cpp
@@ -50,9 +50,13 @@ int main(int argc, char **argv) {
     B b = B(3);
 
     // TODO: 补全三个类型的大小
-    static_assert(sizeof(X) == ?, "There is an int in X");
-    static_assert(sizeof(A) == ?, "There is an int in A");
-    static_assert(sizeof(B) == ?, "B is an A with an X");
+    //static_assert(sizeof(X) == ?, "There is an int in X");
+    //static_assert(sizeof(A) == ?, "There is an int in A");
+    //static_assert(sizeof(B) == ?, "B is an A with an X");
+
+    static_assert(sizeof(X) == 4, "There is an int in X");
+    static_assert(sizeof(A) == 4, "There is an int in A");
+    static_assert(sizeof(B) == 8, "B is an A with an X");
 
     i = 0;
     std::cout << std::endl
diff --git a/exercises/18_class_virtual/main.cpp b/exercises/18_class_virtual/main.cpp
index ac6382413..173c526f2 100644
--- a/exercises/18_class_virtual/main.cpp
+++ b/exercises/18_class_virtual/main.cpp
@@ -42,6 +42,8 @@ int main(int argc, char **argv) {
     C c;
     D d;
 
+    /*
+
     ASSERT(a.virtual_name() == '?', MSG);
     ASSERT(b.virtual_name() == '?', MSG);
     ASSERT(c.virtual_name() == '?', MSG);
@@ -51,10 +53,23 @@ int main(int argc, char **argv) {
     ASSERT(c.direct_name() == '?', MSG);
     ASSERT(d.direct_name() == '?', MSG);
 
+    */
+
+    ASSERT(a.virtual_name() == 'A', MSG);
+    ASSERT(b.virtual_name() == 'B', MSG);
+    ASSERT(c.virtual_name() == 'C', MSG);
+    ASSERT(d.virtual_name() == 'C', MSG);
+    ASSERT(a.direct_name() == 'A', MSG);
+    ASSERT(b.direct_name() == 'B', MSG);
+    ASSERT(c.direct_name() == 'C', MSG);
+    ASSERT(d.direct_name() == 'D', MSG);
+
     A &rab = b;
     B &rbc = c;
     C &rcd = d;
 
+    /*
+
     ASSERT(rab.virtual_name() == '?', MSG);
     ASSERT(rbc.virtual_name() == '?', MSG);
     ASSERT(rcd.virtual_name() == '?', MSG);
@@ -62,19 +77,44 @@ int main(int argc, char **argv) {
     ASSERT(rbc.direct_name() == '?', MSG);
     ASSERT(rcd.direct_name() == '?', MSG);
 
+    */
+
+    ASSERT(rab.virtual_name() == 'B', MSG);
+    ASSERT(rbc.virtual_name() == 'C', MSG);
+    ASSERT(rcd.virtual_name() == 'C', MSG);
+    ASSERT(rab.direct_name() == 'A', MSG);
+    ASSERT(rbc.direct_name() == 'B', MSG);
+    ASSERT(rcd.direct_name() == 'C', MSG);
+
     A &rac = c;
     B &rbd = d;
 
+    /*
+
     ASSERT(rac.virtual_name() == '?', MSG);
     ASSERT(rbd.virtual_name() == '?', MSG);
     ASSERT(rac.direct_name() == '?', MSG);
     ASSERT(rbd.direct_name() == '?', MSG);
 
+    */
+
+    ASSERT(rac.virtual_name() == 'C', MSG);
+    ASSERT(rbd.virtual_name() == 'C', MSG);
+    ASSERT(rac.direct_name() == 'A', MSG);
+    ASSERT(rbd.direct_name() == 'B', MSG);
+
     A &rad = d;
 
+    /*
+
     ASSERT(rad.virtual_name() == '?', MSG);
     ASSERT(rad.direct_name() == '?', MSG);
 
+    */
+
+    ASSERT(rad.virtual_name() == 'C', MSG);
+    ASSERT(rad.direct_name() == 'A', MSG);
+
     return 0;
 }
 
diff --git a/exercises/19_class_virtual_destruct/main.cpp b/exercises/19_class_virtual_destruct/main.cpp
index cdd54f74f..9d79662d8 100644
--- a/exercises/19_class_virtual_destruct/main.cpp
+++ b/exercises/19_class_virtual_destruct/main.cpp
@@ -5,61 +5,84 @@
 
 struct A {
     // TODO: 正确初始化静态字段
-    static int num_a = 0;
+    //static int num_a = 0;
+    static int num_a; // 类内声明
 
     A() {
         ++num_a;
+        std::cout<<"construct A"<<std::endl;
     }
-    ~A() {
+    // 必须改成虚析构函数
+    virtual ~A() {
         --num_a;
+        std::cout<<"destruct A"<<std::endl;
     }
 
     virtual char name() const {
         return 'A';
     }
 };
+int A::num_a = 0; // 类外初始化
+
 struct B final : public A {
     // TODO: 正确初始化静态字段
-    static int num_b = 0;
+    //static int num_b = 0;
+    static int num_b; // 类内声明
 
     B() {
         ++num_b;
+        std::cout<<"construct B"<<std::endl;
     }
-    ~B() {
+    // 必须改成虚析构函数
+    virtual ~B() {
         --num_b;
+        std::cout<<"destruct B"<<std::endl;
     }
 
     char name() const final {
         return 'B';
     }
 };
+int B::num_b = 0; // 类外初始化
+
 
 int main(int argc, char **argv) {
     auto a = new A;
     auto b = new B;
-    ASSERT(A::num_a == ?, "Fill in the correct value for A::num_a");
-    ASSERT(B::num_b == ?, "Fill in the correct value for B::num_b");
-    ASSERT(a->name() == '?', "Fill in the correct value for a->name()");
-    ASSERT(b->name() == '?', "Fill in the correct value for b->name()");
+    ASSERT(A::num_a == 2, "Fill in the correct value for A::num_a");
+    ASSERT(B::num_b == 1, "Fill in the correct value for B::num_b");
+    ASSERT(a->name() == 'A', "Fill in the correct value for a->name()");
+    ASSERT(b->name() == 'B', "Fill in the correct value for b->name()");
+
+    std::cout<<"------------------"<<std::endl;
 
     delete a;
     delete b;
     ASSERT(A::num_a == 0, "Every A was destroyed");
     ASSERT(B::num_b == 0, "Every B was destroyed");
 
+    std::cout<<"------------------"<<std::endl;
+
     A *ab = new B;// 派生类指针可以随意转换为基类指针
-    ASSERT(A::num_a == ?, "Fill in the correct value for A::num_a");
-    ASSERT(B::num_b == ?, "Fill in the correct value for B::num_b");
-    ASSERT(ab->name() == '?', "Fill in the correct value for ab->name()");
+    ASSERT(A::num_a == 1, "Fill in the correct value for A::num_a");
+    ASSERT(B::num_b == 1, "Fill in the correct value for B::num_b");
+    ASSERT(ab->name() == 'B', "Fill in the correct value for ab->name()");
+
+    std::cout<<"------------------"<<std::endl;
 
     // TODO: 基类指针无法随意转换为派生类指针，补全正确的转换语句
-    B &bb = *ab;
-    ASSERT(bb.name() == '?', "Fill in the correct value for bb->name()");
+    //B &bb = *ab;
+    B &bb = dynamic_cast<B&>(*ab);
+    ASSERT(bb.name() == 'B', "Fill in the correct value for bb->name()");
+
+    std::cout<<"------------------"<<std::endl;
 
     // TODO: ---- 以下代码不要修改，通过改正类定义解决编译问题 ----
     delete ab;// 通过指针可以删除指向的对象，即使是多态对象
     ASSERT(A::num_a == 0, "Every A was destroyed");
     ASSERT(B::num_b == 0, "Every B was destroyed");
 
+    std::cout<<"------------------"<<std::endl;
+
     return 0;
 }
diff --git a/exercises/20_function_template/main.cpp b/exercises/20_function_template/main.cpp
index cb6d978d3..2189c5d19 100644
--- a/exercises/20_function_template/main.cpp
+++ b/exercises/20_function_template/main.cpp
@@ -2,7 +2,8 @@
 
 // READ: 函数模板 <https://zh.cppreference.com/w/cpp/language/function_template>
 // TODO: 将这个函数模板化
-int plus(int a, int b) {
+template<typename T>
+T plus(T a, T b) {
     return a + b;
 }
 
@@ -14,7 +15,8 @@ int main(int argc, char **argv) {
     ASSERT(plus(1.25f, 2.5f) == 3.75f, "Plus two float");
     ASSERT(plus(1.25, 2.5) == 3.75, "Plus two double");
     // TODO: 修改判断条件使测试通过
-    ASSERT(plus(0.1, 0.2) == 0.3, "How to make this pass?");
+    //ASSERT(plus(0.1, 0.2) == 0.3, "How to make this pass?");
+    ASSERT(std::abs(plus(0.1, 0.2) - 0.3) < 1e-15, "How to make this pass?");
 
     return 0;
 }
diff --git a/exercises/21_runtime_datatype/main.cpp b/exercises/21_runtime_datatype/main.cpp
index 9c4bf376a..a4a86c345 100644
--- a/exercises/21_runtime_datatype/main.cpp
+++ b/exercises/21_runtime_datatype/main.cpp
@@ -18,15 +18,34 @@ struct TaggedUnion {
 };
 
 // TODO: 将这个函数模板化用于 sigmoid_dyn
+/*
 float sigmoid(float x) {
     return 1 / (1 + std::exp(-x));
 }
+*/
+template<typename T>
+T sigmoid(T x) {
+    return 1 / (1 + std::exp(-x));
+}
 
+/*
 TaggedUnion sigmoid_dyn(TaggedUnion x) {
     TaggedUnion ans{x.type};
     // TODO: 根据 type 调用 sigmoid
     return ans;
 }
+*/
+TaggedUnion sigmoid_dyn(TaggedUnion x) {
+    TaggedUnion ans;
+    ans.type = x.type; // 设置返回值的类型
+    if (x.type == DataType::Float) {
+        ans.f = sigmoid(x.f); // 调用float版本的sigmoid
+    } else {
+        ans.d = sigmoid(x.d); // 调用double版本的sigmoid
+    }
+    return ans;
+}
+
 
 // ---- 不要修改以下代码 ----
 int main(int argc, char **argv) {
diff --git a/exercises/22_class_template/main.cpp b/exercises/22_class_template/main.cpp
index 2a702ecc0..03069c70e 100644
--- a/exercises/22_class_template/main.cpp
+++ b/exercises/22_class_template/main.cpp
@@ -1,7 +1,9 @@
 #include "../exercise.h"
+#include <cstring>
 
 // READ: 类模板 <https://zh.cppreference.com/w/cpp/language/class_template>
 
+/*
 template<class T>
 struct Tensor4D {
     unsigned int shape[4];
@@ -31,6 +33,72 @@ struct Tensor4D {
         return *this;
     }
 };
+*/
+
+template<class T>
+struct Tensor4D {
+    unsigned int shape[4];
+    T *data;
+
+    Tensor4D(unsigned int const shape_[4], T const *data_) {
+        // TODO: 填入正确的 shape 并计算 size
+        for (int i = 0; i < 4; ++i) {
+            shape[i] = shape_[i];
+        }
+        unsigned int size = shape[0] * shape[1] * shape[2] * shape[3];
+        data = new T[size];
+        std::memcpy(data, data_, size * sizeof(T));
+    }
+    ~Tensor4D() {
+        delete[] data;
+    }
+
+    // 为了保持简单，禁止复制和移动
+    Tensor4D(Tensor4D const &) = delete;
+    Tensor4D(Tensor4D &&) noexcept = delete;
+
+    // 这个加法需要支持“单向广播”。
+    // 具体来说，`others` 可以具有与 `this` 不同的形状，形状不同的维度长度必须为 1。
+    // `others` 长度为 1 但 `this` 长度不为 1 的维度将发生广播计算。
+    // 例如，`this` 形状为 `[1, 2, 3, 4]`，`others` 形状为 `[1, 2, 1, 4]`，
+    // 则 `this` 与 `others` 相加时，3 个形状为 `[1, 2, 1, 4]` 的子张量各自与 `others` 对应项相加。
+    Tensor4D &operator+=(Tensor4D const &others) {
+        const unsigned int s1 = others.shape[1];
+        const unsigned int s2 = others.shape[2];
+        const unsigned int s3 = others.shape[3];
+        const unsigned int stride1 = s1 * s2 * s3;
+        const unsigned int stride2 = s2 * s3;
+        const unsigned int stride3 = s3;
+
+        for (unsigned int i0 = 0; i0 < shape[0]; ++i0) {
+            for (unsigned int i1 = 0; i1 < shape[1]; ++i1) {
+                for (unsigned int i2 = 0; i2 < shape[2]; ++i2) {
+                    for (unsigned int i3 = 0; i3 < shape[3]; ++i3) {
+                        unsigned int this_idx = i0 * (shape[1] * shape[2] * shape[3])
+                                              + i1 * (shape[2] * shape[3])
+                                              + i2 * shape[3]
+                                              + i3;
+
+                        unsigned int j0 = (others.shape[0] == 1) ? 0 : i0;
+                        unsigned int j1 = (others.shape[1] == 1) ? 0 : i1;
+                        unsigned int j2 = (others.shape[2] == 1) ? 0 : i2;
+                        unsigned int j3 = (others.shape[3] == 1) ? 0 : i3;
+
+                        unsigned int others_idx = j0 * stride1
+                                                + j1 * stride2
+                                                + j2 * stride3
+                                                + j3;
+
+                        data[this_idx] += others.data[others_idx];
+                    }
+                }
+            }
+        }
+        return *this;
+    }
+};
+
+
 
 // ---- 不要修改以下代码 ----
 int main(int argc, char **argv) {
diff --git a/exercises/23_template_const/main.cpp b/exercises/23_template_const/main.cpp
index e0105e168..ec5161130 100644
--- a/exercises/23_template_const/main.cpp
+++ b/exercises/23_template_const/main.cpp
@@ -3,6 +3,7 @@
 
 // READ: 模板非类型实参 <https://zh.cppreference.com/w/cpp/language/template_parameters#%E6%A8%A1%E6%9D%BF%E9%9D%9E%E7%B1%BB%E5%9E%8B%E5%AE%9E%E5%8F%82>
 
+/*
 template<unsigned int N, class T>
 struct Tensor {
     unsigned int shape[N];
@@ -39,32 +40,82 @@ struct Tensor {
         return index;
     }
 };
+*/
+
+
+template<unsigned int N, class T>
+struct Tensor {
+    unsigned int shape[N];
+    T *data;
+
+    Tensor(unsigned int const shape_[N]) {
+        unsigned int size = 1;
+        for (unsigned int i = 0; i < N; ++i) {
+            shape[i] = shape_[i];
+            size *= shape[i];
+        }
+        data = new T[size];
+        std::memset(data, 0, size * sizeof(T));
+    }
+    ~Tensor() {
+        delete[] data;
+    }
+
+    // 为了保持简单，禁止复制和移动
+    Tensor(Tensor const &) = delete;
+    Tensor(Tensor &&) noexcept = delete;
+
+    T &operator[](unsigned int const indices[N]) {
+        return data[data_index(indices)];
+    }
+    T const &operator[](unsigned int const indices[N]) const {
+        return data[data_index(indices)];
+    }
+
+private:
+    unsigned int data_index(unsigned int const indices[N]) const {
+        unsigned int index = 0;
+        for (unsigned int i = 0; i < N; ++i) {
+            ASSERT(indices[i] < shape[i], "Invalid index");
+            unsigned int product = 1;
+            for (unsigned int j = i + 1; j < N; ++j) {
+                product *= shape[j];
+            }
+            index += indices[i] * product;
+        }
+        return index;
+    }
+};
 
 // ---- 不要修改以下代码 ----
 int main(int argc, char **argv) {
     {
-        unsigned int shape[]{2, 3, 4, 5};
-        auto tensor = Tensor<4, int>(shape);
+        unsigned int shape[]{2, 3, 4, 5}; // 张量形状为 [2,3,4,5]，总元素数 = 2*3*4*5 = 120
+        auto tensor = Tensor<4, int>(shape); // 创建四维张量
 
+        // 测试点 1：索引 [0,0,0,0] (索引从0开始)
         unsigned int i0[]{0, 0, 0, 0};
         tensor[i0] = 1;
         ASSERT(tensor[i0] == 1, "tensor[i0] should be 1");
         ASSERT(tensor.data[0] == 1, "tensor[i0] should be 1");
 
+        // 测试点 2：索引 [1,2,3,4] (索引从0开始)
         unsigned int i1[]{1, 2, 3, 4};
-        tensor[i1] = 2;
+        tensor[i1] = 2; // 写入最后一个元素（线性索引 119）
         ASSERT(tensor[i1] == 2, "tensor[i1] should be 2");
         ASSERT(tensor.data[119] == 2, "tensor[i1] should be 2");
     }
     {
-        unsigned int shape[]{7, 8, 128};
-        auto tensor = Tensor<3, float>(shape);
+        unsigned int shape[]{7, 8, 128}; // 张量形状为 [7,8,128]，总元素数 = 7*8*128 = 7168
+        auto tensor = Tensor<3, float>(shape); // 创建三维张量
 
-        unsigned int i0[]{0, 0, 0};
+        // 测试点 1：索引 [0,0,0]
+        unsigned int i0[]{0, 0, 0}; 
         tensor[i0] = 1.f;
         ASSERT(tensor[i0] == 1.f, "tensor[i0] should be 1");
         ASSERT(tensor.data[0] == 1.f, "tensor[i0] should be 1");
 
+        // 测试点 2：索引 [3,4,99]
         unsigned int i1[]{3, 4, 99};
         tensor[i1] = 2.f;
         ASSERT(tensor[i1] == 2.f, "tensor[i1] should be 2");
diff --git a/exercises/24_std_array/main.cpp b/exercises/24_std_array/main.cpp
index c29718d9d..7ae3b7d69 100644
--- a/exercises/24_std_array/main.cpp
+++ b/exercises/24_std_array/main.cpp
@@ -5,24 +5,25 @@
 // READ: std::array <https://zh.cppreference.com/w/cpp/container/array>
 
 // TODO: 将下列 `?` 替换为正确的代码
-int main(int argc, char **argv) {
+int main(int argc, char **argv) 
+{
     {
         std::array<int, 5> arr{{1, 2, 3, 4, 5}};
-        ASSERT(arr.size() == ?, "Fill in the correct value.");
-        ASSERT(sizeof(arr) == ?, "Fill in the correct value.");
+        ASSERT(arr.size() == 5, "Fill in the correct value.");
+        ASSERT(sizeof(arr) == 20, "Fill in the correct value.");
         int ans[]{1, 2, 3, 4, 5};
-        ASSERT(std::memcmp(arr.?, ans, ?) == 0, "Fill in the correct values.");
+        ASSERT(std::memcmp(arr.data(), ans, sizeof(ans)) == 0, "Fill in the correct values.");
     }
     {
         std::array<double, 8> arr;
-        ASSERT(arr.size() == ?, "Fill in the correct value.");
-        ASSERT(sizeof(arr) == ?, "Fill in the correct value.");
+        ASSERT(arr.size() == 8, "Fill in the correct value.");
+        ASSERT(sizeof(arr) == 64, "Fill in the correct value.");
     }
     {
         std::array<char, 21> arr{"Hello, InfiniTensor!"};
-        ASSERT(arr.size() == ?, "Fill in the correct value.");
-        ASSERT(sizeof(arr) == ?, "Fill in the correct value.");
-        ASSERT(std::strcmp(arr.?, "Hello, InfiniTensor!") == 0, "Fill in the correct value.");
+        ASSERT(arr.size() == 21, "Fill in the correct value.");
+        ASSERT(sizeof(arr) == 21, "Fill in the correct value.");
+        ASSERT(std::strcmp(arr.data(), "Hello, InfiniTensor!") == 0, "Fill in the correct value.");
     }
     return 0;
 }
diff --git a/exercises/25_std_vector/main.cpp b/exercises/25_std_vector/main.cpp
index f9e41bb78..0095442be 100644
--- a/exercises/25_std_vector/main.cpp
+++ b/exercises/25_std_vector/main.cpp
@@ -8,81 +8,82 @@
 int main(int argc, char **argv) {
     {
         std::vector<int> vec{1, 2, 3, 4, 5};
-        ASSERT(vec.size() == ?, "Fill in the correct value.");
+        ASSERT(vec.size() == 5, "Fill in the correct value.");
         // THINK: `std::vector` 的大小是什么意思？与什么有关？
-        ASSERT(sizeof(vec) == ?, "Fill in the correct value.");
+        ASSERT(sizeof(vec) == 24, "Fill in the correct value.");
         int ans[]{1, 2, 3, 4, 5};
-        ASSERT(std::memcmp(vec.?, ans, sizeof(ans)) == 0, "Fill in the correct values.");
+        ASSERT(std::memcmp(vec.data(), ans, sizeof(ans)) == 0, "Fill in the correct values.");
     }
     {
         std::vector<double> vec{1, 2, 3, 4, 5};
         {
-            ASSERT(vec.size() == ?, "Fill in the correct value.");
-            ASSERT(sizeof(vec) == ?, "Fill in the correct value.");
+            ASSERT(vec.size() == 5, "Fill in the correct value.");
+            ASSERT(sizeof(vec) == 24, "Fill in the correct value.");
             double ans[]{1, 2, 3, 4, 5};
-            ASSERT(std::memcmp(vec.?, ans, sizeof(ans)) == 0, "Fill in the correct values.");
+            ASSERT(std::memcmp(vec.data(), ans, sizeof(ans)) == 0, "Fill in the correct values.");
         }
         {
             vec.push_back(6);
-            ASSERT(vec.size() == ?, "Fill in the correct value.");
-            ASSERT(sizeof(vec) == ?, "Fill in the correct value.");
+            ASSERT(vec.size() == 6, "Fill in the correct value.");
+            ASSERT(sizeof(vec) == 24, "Fill in the correct value.");
             vec.pop_back();
-            ASSERT(vec.size() == ?, "Fill in the correct value.");
-            ASSERT(sizeof(vec) == ?, "Fill in the correct value.");
+            ASSERT(vec.size() == 5, "Fill in the correct value.");
+            ASSERT(sizeof(vec) == 24, "Fill in the correct value.");
         }
         {
             vec[4] = 6;
-            ASSERT(vec[0] == ?, "Fill in the correct value.");
-            ASSERT(vec[1] == ?, "Fill in the correct value.");
-            ASSERT(vec[2] == ?, "Fill in the correct value.");
-            ASSERT(vec[3] == ?, "Fill in the correct value.");
-            ASSERT(vec[4] == ?, "Fill in the correct value.");
+            ASSERT(vec[0] == 1, "Fill in the correct value.");
+            ASSERT(vec[1] == 2, "Fill in the correct value.");
+            ASSERT(vec[2] == 3, "Fill in the correct value.");
+            ASSERT(vec[3] == 4, "Fill in the correct value.");
+            ASSERT(vec[4] == 6, "Fill in the correct value.");
         }
         {
             // THINK: `std::vector` 插入删除的时间复杂度是什么？
-            vec.insert(?, 1.5);
+            // 这里要改成+v.begin()
+            vec.insert(vec.begin() + 1, 1.5);
             ASSERT((vec == std::vector<double>{1, 1.5, 2, 3, 4, 6}), "Make this assertion pass.");
-            vec.erase(?);
+            vec.erase(vec.begin() + 3);
             ASSERT((vec == std::vector<double>{1, 1.5, 2, 4, 6}), "Make this assertion pass.");
         }
         {
             vec.shrink_to_fit();
-            ASSERT(vec.capacity() == ?, "Fill in the correct value.");
+            ASSERT(vec.capacity() == 5, "Fill in the correct value.");
             vec.clear();
             ASSERT(vec.empty(), "`vec` is empty now.");
-            ASSERT(vec.size() == ?, "Fill in the correct value.");
-            ASSERT(vec.capacity() == ?, "Fill in the correct value.");
+            ASSERT(vec.size() == 0, "Fill in the correct value.");
+            ASSERT(vec.capacity() == 5, "Fill in the correct value.");
         }
     }
     {
-        std::vector<char> vec(?, ?); // TODO: 调用正确的构造函数
+        std::vector<char> vec(48, 'z'); // TODO: 调用正确的构造函数
         ASSERT(vec[0] == 'z', "Make this assertion pass.");
         ASSERT(vec[47] == 'z', "Make this assertion pass.");
         ASSERT(vec.size() == 48, "Make this assertion pass.");
-        ASSERT(sizeof(vec) == ?, "Fill in the correct value.");
+        ASSERT(sizeof(vec) == 24, "Fill in the correct value.");
         {
             auto capacity = vec.capacity();
             vec.resize(16);
-            ASSERT(vec.size() == ?, "Fill in the correct value.");
-            ASSERT(vec.capacity() == ?, "Fill in a correct identifier.");
+            ASSERT(vec.size() == 16, "Fill in the correct value.");
+            ASSERT(vec.capacity() == capacity, "Fill in a correct identifier.");
         }
         {
             vec.reserve(256);
-            ASSERT(vec.size() == ?, "Fill in the correct value.");
-            ASSERT(vec.capacity() == ?, "Fill in the correct value.");
+            ASSERT(vec.size() == 16, "Fill in the correct value.");
+            ASSERT(vec.capacity() == 256, "Fill in the correct value.");
         }
         {
             vec.push_back('a');
             vec.push_back('b');
             vec.push_back('c');
             vec.push_back('d');
-            ASSERT(vec.size() == ?, "Fill in the correct value.");
-            ASSERT(vec.capacity() == ?, "Fill in the correct value.");
-            ASSERT(vec[15] == ?, "Fill in the correct value.");
-            ASSERT(vec[?] == 'a', "Fill in the correct value.");
-            ASSERT(vec[?] == 'b', "Fill in the correct value.");
-            ASSERT(vec[?] == 'c', "Fill in the correct value.");
-            ASSERT(vec[?] == 'd', "Fill in the correct value.");
+            ASSERT(vec.size() == 20, "Fill in the correct value.");
+            ASSERT(vec.capacity() == 256, "Fill in the correct value.");
+            ASSERT(vec[15] == 'z', "Fill in the correct value.");
+            ASSERT(vec[16] == 'a', "Fill in the correct value.");
+            ASSERT(vec[17] == 'b', "Fill in the correct value.");
+            ASSERT(vec[18] == 'c', "Fill in the correct value.");
+            ASSERT(vec[19] == 'd', "Fill in the correct value.");
         }
     }
 
diff --git a/exercises/26_std_vector_bool/main.cpp b/exercises/26_std_vector_bool/main.cpp
index b4ab4f9c4..c9ba17f74 100644
--- a/exercises/26_std_vector_bool/main.cpp
+++ b/exercises/26_std_vector_bool/main.cpp
@@ -6,29 +6,30 @@
 
 // TODO: 将下列 `?` 替换为正确的代码
 int main(int argc, char **argv) {
-    std::vector<bool> vec(?, ?);// TODO: 正确调用构造函数
+    std::vector<bool> vec(100, true);// TODO: 正确调用构造函数
     ASSERT(vec[0], "Make this assertion pass.");
     ASSERT(vec[99], "Make this assertion pass.");
     ASSERT(vec.size() == 100, "Make this assertion pass.");
     // NOTICE: 平台相关！注意 CI:Ubuntu 上的值。
     std::cout << "sizeof(std::vector<bool>) = " << sizeof(std::vector<bool>) << std::endl;
-    ASSERT(sizeof(vec) == ?, "Fill in the correct value.");
+    // ????? 这个答案似乎与编译器相关
+    ASSERT(sizeof(vec) == 40, "Fill in the correct value.");
     {
         vec[20] = false;
-        ASSERT(?vec[20], "Fill in `vec[20]` or `!vec[20]`.");
+        ASSERT(!vec[20], "Fill in `vec[20]` or `!vec[20]`.");
     }
     {
         vec.push_back(false);
-        ASSERT(vec.size() == ?, "Fill in the correct value.");
-        ASSERT(?vec[100], "Fill in `vec[100]` or `!vec[100]`.");
+        ASSERT(vec.size() == 101, "Fill in the correct value.");
+        ASSERT(!vec[100], "Fill in `vec[100]` or `!vec[100]`.");
     }
     {
         auto ref = vec[30];
-        ASSERT(?ref, "Fill in `ref` or `!ref`");
+        ASSERT(ref, "Fill in `ref` or `!ref`");
         ref = false;
-        ASSERT(?ref, "Fill in `ref` or `!ref`");
+        ASSERT(!ref, "Fill in `ref` or `!ref`");
         // THINK: WHAT and WHY?
-        ASSERT(?vec[30], "Fill in `vec[30]` or `!vec[30]`.");
+        ASSERT(!vec[30], "Fill in `vec[30]` or `!vec[30]`.");
     }
     return 0;
 }
diff --git a/exercises/27_strides/main.cpp b/exercises/27_strides/main.cpp
index baceaf2a9..98a8a112f 100644
--- a/exercises/27_strides/main.cpp
+++ b/exercises/27_strides/main.cpp
@@ -13,6 +13,7 @@ using udim = unsigned int;
 /// @brief 计算连续存储张量的步长
 /// @param shape 张量的形状
 /// @return 张量每维度的访问步长
+/*
 std::vector<udim> strides(std::vector<udim> const &shape) {
     std::vector<udim> strides(shape.size());
     // TODO: 完成函数体，根据张量形状计算张量连续存储时的步长。
@@ -20,6 +21,19 @@ std::vector<udim> strides(std::vector<udim> const &shape) {
     //       使用逆向迭代器可能可以简化代码
     return strides;
 }
+*/
+
+std::vector<udim> strides(std::vector<udim> const &shape) {
+    std::vector<udim> result(shape.size());
+    udim cumulative = 1;
+    auto s_it = shape.rbegin();
+    auto r_it = result.rbegin();
+    for (; s_it != shape.rend(); ++s_it, ++r_it) {
+        *r_it = cumulative;
+        cumulative *= *s_it;
+    }
+    return result;
+}
 
 // ---- 不要修改以下代码 ----
 int main(int argc, char **argv) {
diff --git a/exercises/28_std_string/main.cpp b/exercises/28_std_string/main.cpp
index d8b276274..5fcfdf31d 100644
--- a/exercises/28_std_string/main.cpp
+++ b/exercises/28_std_string/main.cpp
@@ -10,9 +10,9 @@ int main(int argc, char **argv) {
     auto world = "world";
     // READ: `decltype` 表达式 <https://zh.cppreference.com/w/cpp/language/decltype>
     // READ: `std::is_same_v` 元编程判别 <https://zh.cppreference.com/w/cpp/types/is_same>
-    ASSERT((std::is_same_v<decltype(hello), ?>), "Fill in the missing type.");
-    ASSERT((std::is_same_v<decltype(world), ?>), "Fill in the missing type.");
+    ASSERT((std::is_same_v<decltype(hello), std::string>), "Fill in the missing type.");
+    ASSERT((std::is_same_v<decltype(world), const char*>), "Fill in the missing type.");
     // TODO: 将 `?` 替换为正确的字符串
-    ASSERT(hello + ", " + world + '!' == "?", "Fill in the missing string.");
+    ASSERT(hello + ", " + world + '!' == "Hello, world!", "Fill in the missing string.");
     return 0;
 }
diff --git a/exercises/29_std_map/main.cpp b/exercises/29_std_map/main.cpp
index fcccca347..47d024f47 100644
--- a/exercises/29_std_map/main.cpp
+++ b/exercises/29_std_map/main.cpp
@@ -7,11 +7,13 @@
 template<class k, class v>
 bool key_exists(std::map<k, v> const &map, k const &key) {
     // TODO: 实现函数
+    return map.count(key);
 }
 
 template<class k, class v>
 void set(std::map<k, v> &map, k key, v value) {
     // TODO: 实现函数
+    map[key]=value;
 }
 
 // ---- 不要修改以下代码 ----
diff --git a/exercises/30_std_unique_ptr/main.cpp b/exercises/30_std_unique_ptr/main.cpp
index 9b98b5794..820ac4809 100644
--- a/exercises/30_std_unique_ptr/main.cpp
+++ b/exercises/30_std_unique_ptr/main.cpp
@@ -53,8 +53,12 @@ int main(int argc, char **argv) {
         {"fd"},
         // TODO: 分析 problems[1] 中资源的生命周期，将记录填入 `std::vector`
         // NOTICE: 此题结果依赖对象析构逻辑，平台相关，提交时以 CI 实际运行平台为准
-        {"", "", "", "", "", "", "", ""},
-        {"", "", "", "", "", "", "", ""},
+        //{"", "", "", "", "", "", "", ""},
+        //{"", "", "", "", "", "", "", ""},
+        // 问题1的答案
+        {"d", "ffr"},
+        // 问题2的答案
+        {"d", "d", "r"},
     };
 
     // ---- 不要修改以下代码 ----
diff --git a/exercises/31_std_shared_ptr/main.cpp b/exercises/31_std_shared_ptr/main.cpp
index febbbcc6f..10da33780 100644
--- a/exercises/31_std_shared_ptr/main.cpp
+++ b/exercises/31_std_shared_ptr/main.cpp
@@ -5,6 +5,8 @@
 // READ: `std::weak_ptr` <https://zh.cppreference.com/w/cpp/memory/weak_ptr>
 
 // TODO: 将下列 `?` 替换为正确的值
+
+/*
 int main(int argc, char **argv) {
     auto shared = std::make_shared<int>(10);
     std::shared_ptr<int> ptrs[]{shared, shared, shared};
@@ -43,3 +45,44 @@ int main(int argc, char **argv) {
 
     return 0;
 }
+*/
+
+// TODO: 将下列 `?` 替换为正确的值
+int main(int argc, char **argv) {
+    auto shared = std::make_shared<int>(10);
+    std::shared_ptr<int> ptrs[]{shared, shared, shared};
+
+    std::weak_ptr<int> observer = shared;
+    ASSERT(observer.use_count() == 4, "");
+
+    ptrs[0].reset();
+    ASSERT(observer.use_count() == 3, "");
+
+    ptrs[1] = nullptr;
+    ASSERT(observer.use_count() == 2, "");
+
+    ptrs[2] = std::make_shared<int>(*shared);
+    ASSERT(observer.use_count() == 1, "");
+
+    ptrs[0] = shared;
+    ptrs[1] = shared;
+    ptrs[2] = std::move(shared);
+    ASSERT(observer.use_count() == 3, "");
+
+    std::ignore = std::move(ptrs[0]);
+    ptrs[1] = std::move(ptrs[1]);
+    ptrs[1] = std::move(ptrs[2]);
+    ASSERT(observer.use_count() == 2, "");
+
+    shared = observer.lock();
+    ASSERT(observer.use_count() == 3, "");
+
+    shared = nullptr;
+    for (auto &ptr : ptrs) ptr = nullptr;
+    ASSERT(observer.use_count() == 0, "");
+
+    shared = observer.lock();
+    ASSERT(observer.use_count() == 0, "");
+
+    return 0;
+}
diff --git a/exercises/32_std_transform/main.cpp b/exercises/32_std_transform/main.cpp
index f4dc25a5c..713101345 100644
--- a/exercises/32_std_transform/main.cpp
+++ b/exercises/32_std_transform/main.cpp
@@ -9,7 +9,10 @@
 int main(int argc, char **argv) {
     std::vector<int> val{8, 13, 21, 34, 55};
     // TODO: 调用 `std::transform`，将 `v` 中的每个元素乘以 2，并转换为字符串，存入 `ans`
-    // std::vector<std::string> ans
+    std::vector<std::string> ans;
+    // 调用std::transform，使用back_inserter自动填充ans
+    std::transform(val.begin(), val.end(), std::back_inserter(ans),
+               [](int x) { return std::to_string(x * 2); });
     ASSERT(ans.size() == val.size(), "ans size should be equal to val size");
     ASSERT(ans[0] == "16", "ans[0] should be 16");
     ASSERT(ans[1] == "26", "ans[1] should be 26");
diff --git a/exercises/33_std_accumulate/main.cpp b/exercises/33_std_accumulate/main.cpp
index 6326929d5..bc1e7cab4 100644
--- a/exercises/33_std_accumulate/main.cpp
+++ b/exercises/33_std_accumulate/main.cpp
@@ -12,6 +12,12 @@ int main(int argc, char **argv) {
     //       - 连续存储；
     //       的张量占用的字节数
     // int size =
+    int element_count = std::accumulate(
+        std::begin(shape), std::end(shape), 
+        1, 
+        std::multiplies<int>()
+    );
+    int size = element_count * sizeof(DataType); // 总字节数
     ASSERT(size == 602112, "4x1x3x224x224 = 602112");
     return 0;
 }