leetcode 110-判断一棵树是否为平衡二叉树 #算法#

a binary tree in which the depth of the two subtrees of every node never differ by more than 1.
任何节点的两棵子树的深度差不能大于一。

class Solution {
public:
    int depth(TreeNode* root){
        if(root == NULL) return 0;
        int leftDepth = depth(root->left);
        int rightDepth = depth(root->right);
        return (leftDepth > rightDepth ? leftDepth : rightDepth) + 1;
    }
    
    bool isBalanced(TreeNode* root) {
        if(root == NULL) return true;
        return abs(depth(root->left) - depth(root->right)) <= 1 
            && isBalanced(root->left) 
            && isBalanced(root->right);
    }
};