LeetCode Q112: Path Sum

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 path 5->4->11->2 which sum is 22.

	/**
	* 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:
	bool helper(TreeNode* node, int sum, int pathSum){
	pathSum=pathSum+node->val;
	if(node->left==NULL&&node->right==NULL){
	if(pathSum==sum)
	return true;
	else
	return false;
	}
	bool r0=false, r1=false;
	if(node->left!=NULL)
	r0=helper(node->left, sum, pathSum);
	if(node->right!=NULL)
	r1=helper(node->right, sum, pathSum);
	return r0||r1;
	}
	bool hasPathSum(TreeNode* root, int sum) {
	if(root==NULL)
	return false;
	bool res=helper(root, sum, 0);
	return res;
	}
	};

view raw Q112PathSum.cpp hosted with ❤ by GitHub