Path Sum

Q:

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:

Must be root-to-leaf path.

/** * 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) {        if (root == null)            return false;        Queue<TreeNode> consumer = new LinkedList<TreeNode>();        consumer.offer(root);        boolean hasPath = false;        while (!consumer.isEmpty()) {            TreeNode temp = consumer.poll();            if (temp.val == sum) {                if (temp.left == null && temp.right == null)                    hasPath = true;            }            if (temp.left != null) {                int leftsum = temp.val + temp.left.val;                TreeNode newleft = temp.left;                newleft.val = leftsum;                consumer.offer(newleft);            }            if (temp.right != null) {                int rightsum = temp.val + temp.right.val;                TreeNode newright = temp.right;                newright.val = rightsum;                consumer.offer(newright);            }        }        return hasPath;    }}