lintcode: 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.

/**
 * Definition of TreeNode:
 * class TreeNode {
 * public:
 *     int val;
 *     TreeNode *left, *right;
 *     TreeNode(int val) {
 *         this->val = val;
 *         this->left = this->right = NULL;
 *     }
 * }
 */
class Solution {
public:
    /**
     * @param root: The root of binary tree.
     * @return: True if this Binary tree is Balanced, or false.
     */
    int height(TreeNode *node){
        if(node==NULL){
            return 0;
        }
        return max(height(node->left),height(node->right))+1;
    }


    bool isBalanced(TreeNode *root) {
        // write your code here

        if(root==NULL){
            return true;
        }

        int diff=height(root->left)-height(root->right);
        if(diff>1||diff<-1){
            return false;
        }

        return isBalanced(root->left) && isBalanced(root->right);
    }
};

​​​https://haozhou.gitbooks.io/leetcode-java/content/binarytree/binarytree-balanced.html​​