题目描述

2021. Moving Pebbles Two players play the following game. At the beginning of the game they start with n (1<=n<=100000) piles of stones. At each step of the game, the player chooses a pile and remove at least one stone from this pile and move zero or more stones from this pile to any other pile that still has stones. A player loses if he has no more possible moves. Given the initial piles, determine who wins: the first player, or the second player, if both play perfectly. 给你N堆Stone，两个人玩游戏. 每次任选一堆，首先拿掉至少一个石头,然后移动任意个石子到任意堆中. 谁不能移动了，谁就输了...

输入格式

Each line of input has integers 0 < n <= 100000, followed by n positive integers denoting the initial piles.

输出格式

For each line of input, output "first player" if first player can force a win, or "second player", if the second player can force a win.

3 2 1 3

first player

数据范围与约定

鸣谢lqp18_31..