Method check

CPP/Trees/BalancedBinarytrees.cpp:15–22

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