Merge branch 'youngyangyang04:master' into master

Author: nullptr-z

problems/0028.实现strStr.md

@@ -425,8 +425,8 @@ public:
         if (needle.size() == 0) {
             return 0;
         }
-        int next[needle.size()];
-        getNext(next, needle);
+		vector<int> next(needle.size());
+		getNext(&next[0], needle);
         int j = -1; // // 因为next数组里记录的起始位置为-1
         for (int i = 0; i < haystack.size(); i++) { // 注意i就从0开始
             while(j >= 0 && haystack[i] != needle[j + 1]) { // 不匹配
@@ -524,8 +524,8 @@ public:
         if (needle.size() == 0) {
             return 0;
         }
-        int next[needle.size()];
-        getNext(next, needle);
+        vector<int> next(needle.size());
+        getNext(&next[0], needle);
         int j = 0;
         for (int i = 0; i < haystack.size(); i++) {
             while(j > 0 && haystack[i] != needle[j]) {
@@ -1428,4 +1428,3 @@ public int[] GetNext(string needle)
 <a href="https://programmercarl.com/other/kstar.html" target="_blank">
   <img src="../pics/网站星球宣传海报.jpg" width="1000"/>
 </a>
-

problems/0045.跳跃游戏II.md

@@ -285,6 +285,34 @@ class Solution:
 
 ### Go
 
+
+```go
+/**
+ * @date: 2024 Jan 06
+ * @time: 13:44
+ * @author: Chris
+**/
+// 贪心算法优化版
+
+// 记录步骤规则：每超过上一次可达最大范围，需要跳跃一次，次数+1
+// 记录位置：i == lastDistance + 1
+func jump(nums []int) int {
+	// 根据题目规则，初始位置为nums[0]
+	lastDistance := 0 // 上一次覆盖范围
+	curDistance := 0  // 当前覆盖范围（可达最大范围）
+	minStep := 0      // 记录最少跳跃次数
+
+	for i := 0; i < len(nums); i++ {
+		if i == lastDistance+1 { // 在上一次可达范围+1的位置，记录步骤
+			minStep++                  // 跳跃次数+1
+			lastDistance = curDistance // 记录时才可以更新
+		}
+		curDistance = max(nums[i]+i, curDistance) // 更新当前可达的最大范围
+	}
+	return minStep
+}
+```
+
 ```go
 // 贪心版本一
 func jump(nums []int) int {

problems/0116.填充每个节点的下一个右侧节点指针.md

@@ -358,7 +358,84 @@ function connect(root: NodePro | null): NodePro | null {
 };
 ```
 
+```csharp
+//递归
+public class Solution {
+    public Node Connect(Node root) {
+        if (root == null) {
+            return null;
+        }
+        
+        ConnectNodes(root.left, root.right);
+        
+        return root;
+    }
+
+    private void ConnectNodes(Node node1, Node node2) {
+        if (node1 == null || node2 == null) {
+            return;
+        }
+
+        // 将左子节点的 next 指向右子节点
+        node1.next = node2;
+
+        // 递归连接当前节点的左右子节点
+        ConnectNodes(node1.left, node1.right);
+        ConnectNodes(node2.left, node2.right);
+
+        // 连接跨越父节点的两个子树
+        ConnectNodes(node1.right, node2.left);
+    }
+}
+
+
+// 迭代
+public class Solution
+{
+    public Node Connect(Node root)
+    {
+        Queue<Node> que = new Queue<Node>();
+
+        if (root != null)
+        {
+            que.Enqueue(root);
+        }
 
+        while (que.Count > 0)
+        {
+
+            var queSize = que.Count;
+            for (int i = 0; i < queSize; i++)
+            {
+                var cur = que.Dequeue();
+
+                // 当这个节点不是这一层的最后的节点
+                if (i != queSize - 1)
+                {
+                    // 当前节点指向下一个节点
+                    cur.next = que.Peek();
+                }
+                // 否则指向空
+                else
+                {
+                    cur.next = null;
+                }
+
+                if (cur.left != null)
+                {
+                    que.Enqueue(cur.left);
+                }
+                if (cur.right != null)
+                {
+                    que.Enqueue(cur.right);
+                }
+            }
+        }
+
+        return root;
+    }
+}
+```
 
 
 <p align="center">

problems/0200.岛屿数量.深搜版.md

@@ -389,50 +389,41 @@ function numIslands(grid: string[][]): number {
 ### Go
 
 ```go
+
+var DIRECTIONS = [4][2]int{{-1, 0}, {0, -1}, {1, 0}, {0, 1}}
+
 func numIslands(grid [][]byte) int {
-    // 用1标记已访问
-    visited := make([][]int, len(grid))
-    for i := 0; i < len(visited); i++{
-        visited[i] = make([]int, len(grid[0]))
-    }
+	res := 0
 
-    var bfs func(x, y int)
-    bfs = func(x, y int){
-        stack := make([][]int, 0)
-        stack = append(stack, []int{x, y})
-        moveX := []int{1, -1, 0, 0}
-        moveY := []int{0, 0, 1, -1} 
-
-        for len(stack) != 0{
-            node := stack[len(stack) - 1]
-            stack = stack[:len(stack) - 1]
-
-            for i := 0; i < 4; i++{
-                dx := moveX[i] + node[0]
-                dy := moveY[i] + node[1]
-                if dx < 0 || dx >= len(grid) || dy < 0 || dy >= len(grid[0]) || visited[dx][dy] == 1{
-                    continue
-                }
-                visited[dx][dy] = 1
-                if grid[dx][dy] == '1'{
-                    stack = append(stack, []int{dx,dy})
-                }
-            }
-        }
-    }
+	visited := make([][]bool, len(grid))
+	for i := 0; i < len(grid); i++ {
+		visited[i] = make([]bool, len(grid[0]))
+	}
 
-    result := 0
-    for i := 0; i < len(grid); i++{
-        for j := 0; j < len(grid[0]); j++{
-            if visited[i][j] == 0 && grid[i][j] == '1'{
-                bfs(i, j)
-                visited[i][j] = 1
-                result++
-            }
-        }
-    }
+	for i, rows := range grid {
+		for j, v := range rows {
+			if v == '1' && !visited[i][j] {
+				res++
+				dfs(grid, visited, i, j)
+			}
+		}
+	}
+
+	return res
+}
+
+func dfs(grid [][]byte, visited [][]bool, i, j int) {
+        visited[x][y] = true
+	for _, d := range DIRECTIONS {
+		x, y := i+d[0], j+d[1]
+		if x < 0 || x >= len(grid) || y < 0 || y >= len(grid[0]) {
+			continue
+		}
+		if grid[x][y] == '1' && !visited[x][y] {
+			dfs(grid, visited, x, y)
+		}
+	}
 
-    return result
 }
 ```
 

problems/0225.用队列实现栈.md

@@ -1046,6 +1046,8 @@ class MyStack() {
 
 ### C#:
 
+> 双队列
+
 ```csharp
 public class MyStack {
     Queue<int> queue1;
@@ -1080,6 +1082,54 @@ public class MyStack {
 }
 ```
 
+> 单队列
+
+```c#
+/*
+ * @lc app=leetcode id=225 lang=csharp
+ * 版本二：单队列
+ * [225] Implement Stack using Queues
+ */
+
+// @lc code=start
+public class MyStack {
+    Queue<int> myQueue;
+    public MyStack() {
+        myQueue = new Queue<int>();
+    }
+    
+    public void Push(int x) {
+        myQueue.Enqueue(x);
+    }
+    
+    //使用一个队列实现
+    public int Pop() {
+        //一个队列在模拟栈弹出元素的时候只要将队列头部的元素（除了最后一个元素外） 重新添加到队列尾部，此时再去弹出元素就是栈的顺序了。
+        for (var i = 0; i < myQueue.Count-1; i++)
+        {
+            myQueue.Enqueue(myQueue.Dequeue());
+        }
+        return myQueue.Dequeue();
+    }
+
+    //复用Pop()的代码
+    public int Top() {
+        int res = Pop();
+        myQueue.Enqueue(res);
+        return res;
+    }
+    
+    public bool Empty() {
+        return (myQueue.Count == 0);
+    }
+}
+
+// @lc code=end
+
+```
+
+
+
 ### PHP:
 
 > 双队列
@@ -1203,3 +1253,4 @@ impl MyStack {
 <a href="https://programmercarl.com/other/kstar.html" target="_blank">
   <img src="../pics/网站星球宣传海报.jpg" width="1000"/>
 </a>
+