RootToLeafPathWithSum

/**
 * Definition for binary tree
 * struct TreeNode {
 *     int val;
 *     TreeNode *left;
 *     TreeNode *right;
 *     TreeNode(int x) : val(x), left(NULL), right(NULL) {}
 * };
 */
 void path(TreeNode * root,vector<int> &v2,int sum,vector<vector<int> > &v1)
 {
     if(root==NULL)
      return ;
      sum-=root->val;
     v2.push_back(root->val);
     if(root->left==NULL && root->right==NULL)
     {
         if(sum==0)
         {
             v1.push_back(v2);
             
         }
         v2.pop_back();
             return ;
         
     }
     path(root->left,v2,sum,v1);
     path(root->right,v2,sum,v1);
     v2.pop_back();
     return;
 }
vector<vector<int> > Solution::pathSum(TreeNode* root, int sum) {
    // Do not write main() function.
    // Do not read input, instead use the arguments to the function.
    // Do not print the output, instead return values as specified
    // Still have a doubt. Checkout www.interviewbit.com/pages/sample_codes/ for more details
    vector<vector<int> > v1;
    vector<int> v2;
    path(root,v2,sum,v1);
    return v1;
}