Problem112.java

class Problem112 {

 public static void main(String[] args) {
 Problem112 p = new Problem112();
 TreeNode root = new TreeNode(1);
 root.left = new TreeNode(2);
 root.right = new TreeNode(3);
 root.left.right = new TreeNode(4);
 System.out.println(p.hasPathSum(root, 8));
 }

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

 if (root.val == sum) {
 if (root.left == null && root.right == null) return true;
 return false;
 }

 return hasPathSum(root.left, sum-root.val) || hasPathSum(root.right, sum-root.val);
 }
}