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.
1 class Solution { 2 public boolean hasPathSum(TreeNode root, int sum) { 3 4 if(root==null) return false; 5 6 if (root.left==null && root.right==null && sum-root.val==0) return true; 7 8 return hasPathSum(root.left, sum-root.val) ||hasPathSum(root.right,sum-root.val); 9 10 } 11 }