From 5d8a0b091ced561f0538934245f3e5a64e6ea9f2 Mon Sep 17 00:00:00 2001
From: martisss <2466632626@qq.com>
Date: Thu, 26 Aug 2021 09:47:05 +0800
Subject: [PATCH 1/2] =?UTF-8?q?=E5=88=A0=E9=99=A4=E9=87=8D=E5=A4=8D?=
 =?UTF-8?q?=E4=BB=A3=E7=A0=81=EF=BC=8C=E5=A2=9E=E5=8A=A0N=E5=8F=89?=
 =?UTF-8?q?=E6=A0=91=E6=9C=80=E5=A4=A7=E6=B7=B1=E5=BA=A6=E7=9A=84=E9=80=92?=
 =?UTF-8?q?=E5=BD=92=E4=B8=8E=E5=B1=82=E5=BA=8F=E9=81=8D=E5=8E=86=E5=AE=9E?=
 =?UTF-8?q?=E7=8E=B0?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 problems/0104.二叉树的最大深度.md | 56 +++++++++++++++++------
 1 file changed, 43 insertions(+), 13 deletions(-)

diff --git a/problems/0104.二叉树的最大深度.md b/problems/0104.二叉树的最大深度.md
index d086686d..7adb8bb7 100644
--- a/problems/0104.二叉树的最大深度.md
+++ b/problems/0104.二叉树的最大深度.md
@@ -505,21 +505,51 @@ var maxdepth = function(root) {
 
 二叉树最大深度层级遍历
 ```javascript
-var maxdepth = function(root) {
-    //使用递归的方法 递归三部曲
-    //1. 确定递归函数的参数和返回值
-    const getdepth=function(node){
-    //2. 确定终止条件
-        if(node===null){
-            return 0;
+var maxDepth = function(root) {
+    if(!root) return 0
+    let count = 0
+    const queue = [root]
+    while(queue.length) {
+        let size = queue.length
+        /* 层数+1 */
+        count++
+        while(size--) {
+            let node = queue.shift();
+            node.left && queue.push(node.left);
+            node.right && queue.push(node.right);
         }
-    //3. 确定单层逻辑
-        let leftdepth=getdepth(node.left);
-        let rightdepth=getdepth(node.right);
-        let depth=1+math.max(leftdepth,rightdepth);
-        return depth;
     }
-    return getDepth(root);
+    return count
+};
+```
+
+N叉树的最大深度  递归写法
+```js
+var maxDepth = function(root) {
+    if(!root) return 0
+    let depth = 0
+    for(let node of root.children) {
+        depth = Math.max(depth, maxDepth(node))
+    }
+    return depth + 1
+}
+```
+
+N叉树的最大深度  层序遍历
+```js
+var maxDepth = function(root) {
+    if(!root) return 0
+    let count = 0
+    let queue = [root]
+    while(queue.length) {
+        let size = queue.length
+        count++
+        while(size--) {
+            let node = queue.shift()
+            node && (queue = [...queue, ...node.children])
+        }
+    }
+    return count
 };
 ```
 

From e419a5f90815cf233a6e91ea51c7c23c005e4d22 Mon Sep 17 00:00:00 2001
From: xsduan98 <xsduan1998@163.com>
Date: Thu, 26 Aug 2021 10:29:54 +0800
Subject: [PATCH 2/2] =?UTF-8?q?=E7=AC=AC51=E9=A2=98.N=E7=9A=87=E5=90=8E=20?=
 =?UTF-8?q?=E4=BF=AE=E6=94=B9Java=E4=BB=A3=E7=A0=81?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 problems/0051.N皇后.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/problems/0051.N皇后.md b/problems/0051.N皇后.md
index 5404b620..9cc84cf8 100644
--- a/problems/0051.N皇后.md
+++ b/problems/0051.N皇后.md
@@ -332,7 +332,7 @@ class Solution {
 
     public boolean isValid(int row, int col, int n, char[][] chessboard) {
         // 检查列
-        for (int i=0; i<n; ++i) {
+        for (int i=0; i<row; ++i) { // 相当于剪枝
             if (chessboard[i][col] == 'Q') {
                 return false;
             }