二叉树路径和

public static void route(Node node, int n, Stack stack){    if(node == null)   return;    stack.push(node);    if(node.left==null && node.right==null){        if(stack.sum == n){            System.out.println("Got it");        }    }    if(node.left != null){        route(node.left, n, stack);         }    if(node.right != null){        route(node.right, n, stack);    }    stack.pop();}