feat: add solutions to lc problem: No.2349 (#3312)

Author: yanglbme

solution/2300-2399/2349.Design a Number Container System/README.md

@@ -1,25 +1,27 @@
 class NumberContainers {
 public:
-    map<int, int> mp;
-    map<int, set<int>> t;
-
     NumberContainers() {
     }
 
     void change(int index, int number) {
-        auto it = mp.find(index);
-        if (it != mp.end()) {
-            t[it->second].erase(index);
-            it->second = number;
-        } else
-            mp[index] = number;
-        t[number].insert(index);
+        if (d.contains(index)) {
+            int oldNumber = d[index];
+            g[oldNumber].erase(index);
+            if (g[oldNumber].empty()) {
+                g.erase(oldNumber);
+            }
+        }
+        d[index] = number;
+        g[number].insert(index);
     }
 
     int find(int number) {
-        auto it = t.find(number);
-        return it == t.end() || it->second.empty() ? -1 : *it->second.begin();
+        return g.contains(number) ? *g[number].begin() : -1;
     }
+
+private:
+    unordered_map<int, int> d;
+    unordered_map<int, set<int>> g;
 };
 
 /**

solution/2300-2399/2349.Design a Number Container System/README_EN.md

@@ -1,29 +1,28 @@
 type NumberContainers struct {
-	mp map[int]int
-	t  map[int]*redblacktree.Tree
+	d map[int]int
+	g map[int]*redblacktree.Tree
 }
 
 func Constructor() NumberContainers {
 	return NumberContainers{map[int]int{}, map[int]*redblacktree.Tree{}}
 }
 
 func (this *NumberContainers) Change(index int, number int) {
-	if num, ok := this.mp[index]; ok {
-		this.t[num].Remove(index)
+	if oldNumber, ok := this.d[index]; ok {
+		this.g[oldNumber].Remove(index)
 	}
-	this.mp[index] = number
-	if this.t[number] == nil {
-		this.t[number] = redblacktree.NewWithIntComparator()
+	this.d[index] = number
+	if _, ok := this.g[number]; !ok {
+		this.g[number] = redblacktree.NewWithIntComparator()
 	}
-	this.t[number].Put(index, nil)
+	this.g[number].Put(index, nil)
 }
 
 func (this *NumberContainers) Find(number int) int {
-	s, ok := this.t[number]
-	if !ok || s.Size() == 0 {
-		return -1
+	if ids, ok := this.g[number]; ok && ids.Size() > 0 {
+		return ids.Left().Key.(int)
 	}
-	return s.Left().Key.(int)
+	return -1
 }
 
 /**

solution/2300-2399/2349.Design a Number Container System/Solution.cpp

@@ -1,24 +1,22 @@
 class NumberContainers {
-    private Map<Integer, Integer> mp = new HashMap<>();
-    private Map<Integer, TreeSet<Integer>> t = new HashMap<>();
+    private Map<Integer, Integer> d = new HashMap<>();
+    private Map<Integer, TreeSet<Integer>> g = new HashMap<>();
 
     public NumberContainers() {
     }
 
     public void change(int index, int number) {
-        if (mp.containsKey(index)) {
-            int v = mp.get(index);
-            t.get(v).remove(index);
-            if (t.get(v).isEmpty()) {
-                t.remove(v);
-            }
+        if (d.containsKey(index)) {
+            int oldNumber = d.get(index);
+            g.get(oldNumber).remove(index);
         }
-        mp.put(index, number);
-        t.computeIfAbsent(number, k -> new TreeSet<>()).add(index);
+        d.put(index, number);
+        g.computeIfAbsent(number, k -> new TreeSet<>()).add(index);
     }
 
     public int find(int number) {
-        return t.containsKey(number) ? t.get(number).first() : -1;
+        var ids = g.get(number);
+        return ids == null || ids.isEmpty() ? -1 : ids.first();
     }
 }
 

solution/2300-2399/2349.Design a Number Container System/Solution.go

@@ -2,20 +2,21 @@
 
 
 class NumberContainers:
+
     def __init__(self):
-        self.mp = {}
-        self.t = defaultdict(SortedSet)
+        self.d = {}
+        self.g = defaultdict(SortedSet)
 
     def change(self, index: int, number: int) -> None:
-        if index in self.mp:
-            v = self.mp[index]
-            self.t[v].remove(index)
-        self.mp[index] = number
-        self.t[number].add(index)
+        if index in self.d:
+            old_number = self.d[index]
+            self.g[old_number].remove(index)
+        self.d[index] = number
+        self.g[number].add(index)
 
     def find(self, number: int) -> int:
-        s = self.t[number]
-        return s[0] if s else -1
+        ids = self.g[number]
+        return ids[0] if ids else -1
 
 
 # Your NumberContainers object will be instantiated and called as such:

solution/2300-2399/2349.Design a Number Container System/Solution.java

@@ -59,7 +59,13 @@ tags:
 
 <!-- solution:start -->
 
-### 方法一
+### 方法一：分情况讨论
+
+如果起点和终点相同，那么只有当 $t \neq 1$ 时，才能在给定时间到达终点。
+
+否则，我们可以计算出起点和终点的横纵坐标之差，然后取最大值，如果最大值小于等于给定时间，那么就可以在给定时间到达终点。
+
+时间复杂度 $O(1)$，空间复杂度 $O(1)$。
 
 <!-- tabs:start -->
 
@@ -143,8 +149,9 @@ function isReachableAtTime(sx: number, sy: number, fx: number, fy: number, t: nu
 ```cs
 public class Solution {
     public bool IsReachableAtTime(int sx, int sy, int fx, int fy, int t) {
-        if (sx == fx && sy == fy)
+        if (sx == fx && sy == fy) {
             return t != 1;
+        }
         return Math.Max(Math.Abs(sx - fx), Math.Abs(sy - fy)) <= t;
     }
 }

solution/2300-2399/2349.Design a Number Container System/Solution.py

@@ -57,7 +57,13 @@ tags:
 
 <!-- solution:start -->
 
-### Solution 1
+### Solution 1: Case Discussion
+
+If the starting point and the destination are the same, then we can only reach the destination within the given time if $t \neq 1$.
+
+Otherwise, we can calculate the difference in the x and y coordinates between the starting point and the destination, and then take the maximum value. If the maximum value is less than or equal to the given time, then we can reach the destination within the given time.
+
+The time complexity is $O(1)$, and the space complexity is $O(1)$.
 
 <!-- tabs:start -->
 
@@ -141,8 +147,9 @@ function isReachableAtTime(sx: number, sy: number, fx: number, fy: number, t: nu
 ```cs
 public class Solution {
     public bool IsReachableAtTime(int sx, int sy, int fx, int fy, int t) {
-        if (sx == fx && sy == fy)
+        if (sx == fx && sy == fy) {
             return t != 1;
+        }
         return Math.Max(Math.Abs(sx - fx), Math.Abs(sy - fy)) <= t;
     }
 }

solution/2300-2399/2349.Design a Number Container System/Solution.ts

@@ -1,7 +1,8 @@
 public class Solution {
     public bool IsReachableAtTime(int sx, int sy, int fx, int fy, int t) {
-        if (sx == fx && sy == fy)
+        if (sx == fx && sy == fy) {
             return t != 1;
+        }
         return Math.Max(Math.Abs(sx - fx), Math.Abs(sy - fy)) <= t;
     }
 }