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Balanced Binary Tree 平衡二叉树

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.

 

求二叉树是否平衡,根据题目中的定义,高度平衡二叉树是每一个节点的两个字数的深度差不能超过1,那么我们肯定需要一个求各个点深度的函数,然后对每个节点的两个子树来比较深度差。代码如下:

 

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

 

Balanced Binary Tree 平衡二叉树