balanced-binary-tree

class Solution {
public:
    bool isBalanced(TreeNode *root) {
        return getheight(root)!=-1;
    }
    int getheight(TreeNode*root)
    {
        if(root==NULL)return 0;
        int left=getheight(root->left);
        if(left==-1)return -1;
        int right=getheight(root->right);
        if(right==-1)return -1;
        return abs(left-right)>1?-1:max(left,right)+1;
    }
};