Balanced Binary Tree

class Solution {
public:
    int depth(TreeNode* root)
    {
        if(!root)
            return 0;
        int nleft=depth(root->left);
        int nright=depth(root->right);
        
        return (nleft>nright)?(nleft+1):(nright+1);
    }
    bool isBalanced(TreeNode* root) {
        if(!root)
            return true;
        int leftdepth=depth(root->left);
        int rightdepth=depth(root->right);
        if(leftdepth-rightdepth>1||leftdepth-rightdepth<-1)
            return false;
        return isBalanced(root->left)&&isBalanced(root->right);
    }
};

 

class Solution {
public:
    bool ifBalanced(TreeNode* root,int* depth)
    {
        if(!root)
        {
            *depth=0;
            return true;
        }
        int left, right;
        if(ifBalanced(root->left,&left)&&ifBalanced(root->right,&right))
        {
            if(left-right>=-1&&left-right<=1)
            {
                *depth=1+(left>right?left:right);
                return true;
            }
        }
        return false;
    }
    bool isBalanced(TreeNode* root) {
       int depth=0;
       return ifBalanced(root,&depth);
    }
};