import java.util.ArrayList;

public class PathSum {

ArrayList<Integer> sums = new ArrayList<Integer>();

public boolean hasPathSum(TreeNode root, int sum) {

int s = 0;

if (root == null) {

if (sum == 0) {

return true;

}

else {

return false;

}

}

preorder(root, 0);

for (Integer x: sums) {

if (x == sum) {

return true;

}

}

return false;

}

public void preorder(TreeNode root, int prev) {

if (root.left == null && root.right == null) {

sums.add(prev + root.val);

return;

}

if (root.left != null) {

preorder(root.left, prev + root.val);

}

if (root.right != null) {

preorder(root.right, prev + root.val);

}

}

public void testSum() {

TreeNode root = new TreeNode(5);

root.left = new TreeNode(3);

root.right = new TreeNode(2);

System.out.println(hasPathSum(root, 6));

}

}