Method hasPathSum

Java/path-sum.java:17–39

(TreeNode root, int sum)

 */
class Solution {
    public boolean hasPathSum(TreeNode root, int sum) {
        if(root == null){
            // exception
            return false;
        }
        if(root.left == null && root.right == null){
            if(sum == root.val){
                return true;
            }
            return false;
        }
        else{
            boolean left = false;
            boolean right = false;
            if(root.left != null){
                left = hasPathSum(root.left, sum-root.val);
            }
            if(root.right != null){
                right = hasPathSum(root.right, sum-root.val);
            }
            return left||right;
        }
    }
}