剑指offer 平衡二叉树

class Solution {
public:
    bool IsBalanced_Solution(TreeNode* pRoot) {
        if(pRoot==NULL) return true;
        //求其左右子树的深度差
        int depthLeft=TreeDepth(pRoot->left);
        int depthRight=TreeDepth(pRoot->right);
        int diff=(depthLeft-depthRight);
        int diff2=diff*diff;
        //若左右子树深度差平方大于1，立即返回false
        if(diff2>1){
            return false;
        }
        //若左右子树的深度差平方小于等于1，递归查看其子树
        else{
            return IsBalanced_Solution(pRoot->left)&&IsBalanced_Solution(pRoot->right);
        }
    }
    int TreeDepth(TreeNode* pRoot)
    {
        if(pRoot!=NULL){
            int depthL=TreeDepth(pRoot->left);
            int depthR=TreeDepth(pRoot->right);
            int max=depthL>depthR?depthL:depthR;
            return max+1;
        }else{
            return 0;
        }
    }
};