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

Problem Note

  • A leaf is a node with no children.

Example 1

Input: Given the below binary tree and sum = 22
      5
     / \
    4   8
   /   / \
  11  13  4
 /  \      \
7    2      1
Output: true
Explanation: There exist a root-to-leaf path 5->4->11->2 which sum is 22.