From 8c16a79ea406385fd1520d14016a3373e145c473 Mon Sep 17 00:00:00 2001
From: db <39407623+IcePigZDB@users.noreply.github.com>
Date: Sun, 26 Dec 2021 22:00:18 +0800
Subject: [PATCH] =?UTF-8?q?=E4=BA=8C=E5=8F=89=E6=A0=91=E6=9C=80=E5=A4=A7?=
 =?UTF-8?q?=E6=B7=B1=E5=BA=A6=20null->NULL?=
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---
 problems/0104.二叉树的最大深度.md | 12 ++++++------
 1 file changed, 6 insertions(+), 6 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 82a82fd5..e0cf2b63 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
@@ -48,7 +48,7 @@ int getdepth(treenode* node)
 
 代码如下：
 ```CPP
-if (node == null) return 0;
+if (node == NULL) return 0;
 ```
 
 3. 确定单层递归的逻辑：先求它的左子树的深度，再求的右子树的深度，最后取左右深度最大的数值 再+1 （加1是因为算上当前中间节点）就是目前节点为根节点的树的深度。
@@ -68,7 +68,7 @@ return depth;
 class solution {
 public:
     int getdepth(treenode* node) {
-        if (node == null) return 0;
+        if (node == NULL) return 0;
         int leftdepth = getdepth(node->left);       // 左
         int rightdepth = getdepth(node->right);     // 右
         int depth = 1 + max(leftdepth, rightdepth); // 中
@@ -104,7 +104,7 @@ public:
     void getdepth(treenode* node, int depth) {
         result = depth > result ? depth : result; // 中
 
-        if (node->left == null && node->right == null) return ;
+        if (node->left == NULL && node->right == NULL) return ;
 
         if (node->left) { // 左
             depth++;    // 深度+1
@@ -137,7 +137,7 @@ public:
     int result;
     void getdepth(treenode* node, int depth) {
         result = depth > result ? depth : result; // 中
-        if (node->left == null && node->right == null) return ;
+        if (node->left == NULL && node->right == NULL) return ;
         if (node->left) { // 左
             getdepth(node->left, depth + 1);
         }
@@ -173,7 +173,7 @@ c++代码如下：
 class solution {
 public:
     int maxdepth(treenode* root) {
-        if (root == null) return 0;
+        if (root == NULL) return 0;
         int depth = 0;
         queue<treenode*> que;
         que.push(root);
@@ -238,7 +238,7 @@ class solution {
 public:
     int maxdepth(node* root) {
         queue<node*> que;
-        if (root != null) que.push(root);
+        if (root != NULL) que.push(root);
         int depth = 0;
         while (!que.empty()) {
             int size = que.size();