homework_1

task_01/README.md

@@ -1,3 +1,3 @@
 # Задача 1
 
-Дано целое число и отсортированый массив целых чисел, нужно найти 2 числа из массива которые в сумме дадут заданное число
+Дано целое число и отсортированый массив целых чисел, нужно найти 2 числа из массива которые в сумме дадут заданное число

task_01/file.txt

@@ -0,0 +1 @@
+123

task_01/src/task.cpp

@@ -0,0 +1,65 @@
+#include "task.hpp"
+
+// O(logn)
+int BinSearch(std::vector<int> massive, int num) {
+  int length = massive.size();
+  int left = 0;
+  int right = length - 1;
+  int index = length / 2;
+  while (right - left >= 0) {
+    if (massive[index] == num) {
+      return index;
+    } else if (massive[index] > num) {
+      right = index - 1;
+    } else if (massive[index] < num) {
+      left = index + 1;
+    }
+    index = (right + left) / 2;
+  }
+  return -1;
+}
+
+// O(n^2)
+std::tuple<int, int> NSquareSearch(std::vector<int> massive, int num) {
+  int length = massive.size();
+  for (int i = 0; i < length; i++) {
+    for (int j = i + 1; j < length; j++) {
+      if (massive[i] + massive[j] == num) {
+        return {i, j};
+      }
+    }
+  }
+  return {-1, -1};
+}
+
+// O(nlogn)
+std::tuple<int, int> NLogNSearch(std::vector<int> massive, int num) {
+  int length = massive.size();
+  for (int i = 0; i < length; i++) {
+    int el1 = massive[i];
+    int el2 = num - el1;
+    int j = BinSearch(massive, el2);
+    if (j != -1 && i != j) {
+      return {i, j};
+    }
+  }
+  return {-1, -1};
+}
+
+// O(n)
+std::tuple<int, int> NSearch(std::vector<int> massive, int num) {
+  int length = massive.size();
+  int left = 0;
+  int right = length - 1;
+  while (right != left) {
+    int sum = massive[left] + massive[right];
+    if (sum == num) {
+      return {left, right};
+    } else if (sum < num) {
+      left++;
+    } else if (sum > num) {
+      right--;
+    }
+  }
+  return {-1, -1};
+}

task_01/src/task.hpp

@@ -0,0 +1,17 @@
+#pragma once
+
+#include <iostream>
+#include <tuple>
+#include <vector>
+
+// O(logn)
+int BinSearch(std::vector<int> mas, int num);
+
+// O(n^2)
+std::tuple<int, int> NSquareSearch(std::vector<int> massive, int num);
+
+// O(nlogn)
+std::tuple<int, int> NLogNSearch(std::vector<int> massive, int num);
+
+// O(n)
+std::tuple<int, int> NSearch(std::vector<int> massive, int num);

task_01/src/test.cpp

@@ -1,8 +1,83 @@
 
 #include <gtest/gtest.h>
 
-#include "topology_sort.hpp"
+#include "task.hpp"
 
-TEST(TopologySort, Simple) {
-  ASSERT_EQ(1, 1);  // Stack []
+// BinSearch tests
+TEST(BinSearch, Simple) {
+  // even len
+  std::vector<int> mas = {1, 2, 3, 4, 5, 6, 7, 8};
+  ASSERT_EQ(BinSearch(mas, 1), 0);
+  ASSERT_EQ(BinSearch(mas, 2), 1);
+  ASSERT_EQ(BinSearch(mas, 3), 2);
+  ASSERT_EQ(BinSearch(mas, 4), 3);
+  ASSERT_EQ(BinSearch(mas, 5), 4);
+  ASSERT_EQ(BinSearch(mas, 6), 5);
+  ASSERT_EQ(BinSearch(mas, 7), 6);
+  ASSERT_EQ(BinSearch(mas, 8), 7);
+
+  ASSERT_EQ(BinSearch(mas, 31), -1);
+
+  // odd len
+  mas = {1, 2, 3, 4, 5, 6, 7, 8, 9};
+  ASSERT_EQ(BinSearch(mas, 1), 0);
+  ASSERT_EQ(BinSearch(mas, 2), 1);
+  ASSERT_EQ(BinSearch(mas, 3), 2);
+  ASSERT_EQ(BinSearch(mas, 4), 3);
+  ASSERT_EQ(BinSearch(mas, 5), 4);
+  ASSERT_EQ(BinSearch(mas, 6), 5);
+  ASSERT_EQ(BinSearch(mas, 7), 6);
+  ASSERT_EQ(BinSearch(mas, 8), 7);
+
+  ASSERT_EQ(BinSearch(mas, 31), -1);
+
+  // empty mas
+  mas = {};
+  ASSERT_EQ(BinSearch(mas, 8), -1);
+
+  // mas of 1 elem
+  mas = {1};
+  ASSERT_EQ(BinSearch(mas, 1), 0);
+
+  ASSERT_EQ(BinSearch(mas, 31), -1);
+
+  // mas of 2 elems
+  mas = {1, 2};
+  ASSERT_EQ(BinSearch(mas, 1), 0);
+  ASSERT_EQ(BinSearch(mas, 2), 1);
+
+  ASSERT_EQ(BinSearch(mas, 31), -1);
 }
+
+// NSquareSearch tests
+TEST(NSquareSearch, Simple) {
+  std::vector<int> mas = {1, 2, 3, 4, 5, 6, 7, 8};
+  ASSERT_EQ(NSquareSearch(mas, 11), std::make_tuple(2, 7));
+  ASSERT_EQ(NSquareSearch(mas, 9), std::make_tuple(0, 7));
+
+  ASSERT_EQ(NSquareSearch(mas, 1), std::make_tuple(-1, -1));
+  ASSERT_EQ(NSquareSearch(mas, 16),
+            std::make_tuple(-1, -1));  // not (7, 7), as indexes cant be same
+}
+
+// NLogNSearch tests
+TEST(NLogNSearch, Simple) {
+  std::vector<int> mas = {1, 2, 3, 4, 5, 6, 7, 8};
+  ASSERT_EQ(NLogNSearch(mas, 11), std::make_tuple(2, 7));
+  ASSERT_EQ(NLogNSearch(mas, 9), std::make_tuple(0, 7));
+
+  ASSERT_EQ(NLogNSearch(mas, 1), std::make_tuple(-1, -1));
+  ASSERT_EQ(NLogNSearch(mas, 16),
+            std::make_tuple(-1, -1));  // not (7, 7), as indexes cant be same
+}
+
+// NSearch tests
+TEST(NSearch, Simple) {
+  std::vector<int> mas = {1, 2, 3, 4, 5, 6, 7, 8};
+  ASSERT_EQ(NSearch(mas, 11), std::make_tuple(2, 7));
+  ASSERT_EQ(NSearch(mas, 9), std::make_tuple(0, 7));
+
+  ASSERT_EQ(NSearch(mas, 1), std::make_tuple(-1, -1));
+  ASSERT_EQ(NSearch(mas, 16),
+            std::make_tuple(-1, -1));  // not (7, 7), as indexes cant be same
+}

task_02/src/stack.cpp

@@ -1,21 +1,35 @@
 #include "stack.hpp"
 
 #include <algorithm>
-
-void Stack::Push(int value) { data_.push(value); }
+#include <cstddef>
+#include <utility>
 
 int Stack::Pop() {
-  auto result = data_.top();
-  data_.pop();
+  int result = data_[data_.size() - 1];
+  data_.pop_back();
   return result;
 }
 
-void MinStack::Push(int value) { data_.push_back(value); }
+void MinStack::Push(int value) {
+  std::pair<int, int> new_element;
+  if (current_minimum_ == 1e9) {
+    new_element = {value, value};
+  } else if (value < current_minimum_) {
+    new_element = {value, value};
+  } else {
+    new_element = {value, current_minimum_};
+  }
+  data_.push_back(new_element);
+  current_minimum_ = new_element.second;
+}
 
 int MinStack::Pop() {
-  auto result = data_.back();
+  int result = data_[data_.size() - 1].first;
   data_.pop_back();
+  if (data_.size() == 0) {
+    current_minimum_ = 1e9;
+  } else {
+    current_minimum_ = data_[data_.size() - 1].second;
+  }
   return result;
 }
-
-int MinStack::GetMin() { return *std::min_element(data_.begin(), data_.end()); }

task_02/src/stack.hpp

@@ -1,23 +1,25 @@
 #pragma once
 
 #include <stack>
+#include <utility>
 #include <vector>
 
 class Stack {
  public:
-  void Push(int value);
+  void Push(int value) { data_.push_back(value); }
   int Pop();
 
  private:
-  std::stack<int> data_;
+  std::vector<int> data_;
 };
 
 class MinStack {
  public:
   void Push(int value);
   int Pop();
-  int GetMin();
+  int GetMin() { return current_minimum_; };
 
  private:
-  std::vector<int> data_;
+  std::vector<std::pair<int, int>> data_;
+  int current_minimum_ = 1e9;
 };