LeetCode题目:Balanced Binary Tree

Posted 2020-06-22

Balanced Binary Tree:

Given a binary tree, determine if it is height-balanced.

For this problem, a height-balanced binary tree is defined as a binary tree in which the depth of the two subtrees of every node never differ by more than 1.

 

tags:深度优先遍历

class Solution {
private:
    //求出树的深度
    int depth(TreeNode *root){
        if(NULL == root)
            return 0;
        return max(depth(root->left), depth(root->right)) + 1;
    }
public:
    bool isBalanced(TreeNode* root) {
        if(NULL == root)
            return true;
        //判断是否符合条件
        if(abs(depth(root->left) - depth(root->right)) > 1)
            return false;
        //递归的判断左右子树是否是平衡的
        return isBalanced(root->left) && isBalanced(root->right);
    }
};

感觉这样做会重复计算了子树的深度，不过这样做思路比较清晰。