二叉树遍历应用110. Balanced Binary Tree

最近代码写的巨烂，我也是醉了

/** * Definition for a binary tree node. * struct TreeNode { *     int val; *     TreeNode *left; *     TreeNode *right; *     TreeNode(int x) : val(x), left(NULL), right(NULL) {} * }; */class Solution {public:    bool flag = false;    bool isBalanced(TreeNode* root) {    dfs(root) ;       return !flag;    }    int dfs(TreeNode* root)    {        if (flag || root==NULL)            return 0;        int l = dfs(root->left);        int r = dfs(root->right);        if (abs(r-l)>1)        {            flag = true;            return -1;        }        return (r>l)? r+1: l+1;    }};