Balanced Binary Tree

/**
* Definition for a binary tree node.
* struct TreeNode {
*     int val;
*     TreeNode *left;
*     TreeNode *right;
*     TreeNode(int x) : val(x), left(NULL), right(NULL) {}
* };
*/
class Solution {
public:
int max(int a,int b)
{
return  a>b?a:b;
}
int getDepth(TreeNode * root,bool& flag)
{
if(root==NULL)
return 0;
int leftDep=getDepth(root->left,flag);
int rightDep=getDepth(root->right,flag);
if(rightDep-leftDep<-1||rightDep-leftDep>1)
flag=false;
int dep=max(rightDep,leftDep)+1;
return dep;
}

bool isBalanced(TreeNode* root) {
bool flag=true;
int depth=getDepth(root,flag);
return flag;
}
};