Path Sum in Binary Tree

Problem Statement

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.

Solution

class Solution 
{
	public:
		bool hasPathSum(TreeNode *root, int sum) 
		{ 
			bool l=false,r=false;
			if( root == NULL )
				return false;

			if(root->left == NULL && root->right == NULL)
			{
				if( (sum - root->val) == 0 )
					return true;
				return false;
			}

			if( root->left != NULL )
				l = hasPathSum(root->left,sum-root->val);

			if( root->right != NULL )
				r = hasPathSum(root->right,sum - root->val);

			return l|r;
		}
	
};

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