Leetcode-Path Sum

Leetcode-Path Sum
Path Sum Total Accepted: 31405 Total Submissions: 104326My SubmissionsQuestionSolution

Given a binary tree and a sum, determine if the tree has a root-to-leaf path such that adding up all the values along the path equals the given sum.

For example:
Given the below binary tree and sum = 22,

              5             / \            4   8           /   / \          11  13  4         /  \      \        7    2      1

Return true, as there exist a root-to-leaf path5->4->11->2Which sum is 22.

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/** * Definition for binary tree * struct TreeNode { *     int val; *     TreeNode *left; *     TreeNode *right; *     TreeNode(int x) : val(x), left(NULL), right(NULL) {} * }; */class Solution {public:    int flag=0;    bool hasPathSum(TreeNode *root, int sum) {        if(root==NULL) return false;                pathSum(root,0,sum);                if(flag==1)            return true;        else            return false;            }        int pathSum(TreeNode *root,int res,int sum)    {        if(root==NULL)  return 0;                res+=root->val;                int l=pathSum(root->left,res,sum);        int r=pathSum(root->right,res,sum);                if((l+r)==0&&res==sum)        {            flag=1;        }            }};