week 3 112. Path Sum

/**
 * Definition for a binary tree node.
 * 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;
 
        LinkedList<TreeNode> nodes = new LinkedList<TreeNode>();
        LinkedList<Integer> values = new LinkedList<Integer>();
 
        nodes.add(root);
        values.add(root.val);
 
        while(!nodes.isEmpty()){
            TreeNode curr = nodes.poll();
            int sumValue = values.poll();
 
            if(curr.left == null && curr.right == null && sumValue==sum){
                return true;
            }
 
            if(curr.left != null){
                nodes.add(curr.left);
                values.add(sumValue+curr.left.val);
            }
 
            if(curr.right != null){
                nodes.add(curr.right);
                values.add(sumValue+curr.right.val);
            }
        }
 
        return false;
    }
}