Update 0222.完全二叉树的节点个数.md

problems/0222.完全二叉树的节点个数.md

@@ -80,7 +80,7 @@ return treeNum;
 class Solution {
 private:
     int getNodesNum(TreeNode* cur) {
-        if (cur == 0) return 0;
+        if (cur == NULL) return 0;
         int leftNum = getNodesNum(cur->left);      // 左
         int rightNum = getNodesNum(cur->right);    // 右
         int treeNum = leftNum + rightNum + 1;      // 中