[LeetCode] Path Sum

Total Accepted: 11233Total Submissions:
37402

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 binary tree
* public class TreeNode {
*     int val;
*     TreeNode left;
*     TreeNode right;
*     TreeNode(int x) { val = x; }
* }
*/
public class Solution {
public boolean hasPathSum(TreeNode root, int sum) {
return traverse(root, 0, sum);
}

public boolean traverse(TreeNode root, int sum, int target) {
if (root == null) return false;

sum += root.val;
if (sum == target && root.left == null && root.right == null) return true;

return traverse(root.left, sum, target) || traverse(root.right, sum, target);
}
}