Balanced Binary Tree.txt

/**
 * 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) {
        // Start typing your C/C++ solution below
        // DO NOT write int main() function
        bool ret = true;
        height(root, ret);
        return ret;
    }
    int height(TreeNode* root, bool &ret) {
        if (!root)
            return 0;
        int l = height(root->left, ret);
        int r = height(root->right, ret);
        ret = (abs(l - r) > 1)?false:ret;
        return max(l, r)+1;
    }
};