public:
    
    bool IsBalanced_Solution(TreeNode* pRoot) {
        if(!pRoot)
            return true;
        int left=deep(pRoot->left);
        int right=deep(pRoot->right);
        if(left-right>1||left-right<-1)
            return false;
        return IsBalanced_Solution(pRoot->left)&&IsBalanced_Solution(pRoot->right);
    }
    int deep(TreeNode* root){
        if(!root)
            return 0;
        return max(deep(root->left),deep(root->right))+1;
    }
};