leetcode 110.平衡二叉树

/**
 * Definition for a binary tree node.
 * struct TreeNode {
 *     int val;
 *     TreeNode *left;
 *     TreeNode *right;
 *     TreeNode() : val(0), left(nullptr), right(nullptr) {}
 *     TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}
 *     TreeNode(int x, TreeNode *left, TreeNode *right) : val(x), left(left), right(right) {}
 * };
 */
class Solution {
public:
    int getDeep(TreeNode* root){
        if(root==NULL) return 0;
        int left=getDeep(root->left);
        int right=getDeep(root->right);
        int deep=max(left,right)+1;
        return deep;
    }
    bool isBalanced(TreeNode* root) {
        if(root==NULL) return true;
        if(abs((getDeep(root->left))-(getDeep(root->right)))>1) return false;
        else{
            return isBalanced(root->left)&&isBalanced(root->right);
        }

    }
};

注意递归判断的截至条件