Sum Tree

int fun(Node *root,bool &ans){
    if(!root) return 0;
    if(!root->left && !root->right) return root->data;
    int n1=0,n2=0;
    n1=fun(root->left,ans);
    n2=fun(root->right,ans);
    if(n1+n2!=root->data) ans=false;    //ans will keep track for any position if not works,then ans =false else true
    return n1+n2+root->data;
}
// Should return true if tree is Sum Tree, else false
class Solution
{
    public:
    bool isSumTree(Node* root)
    {    if(!root || (!root->left && !root->right)) return true;
         bool ans=true;
         int temp=fun(root,ans);
         return ans;
    }
};