【Gym

There are two seagulls playing a very peculiar game. First they line up N unit squares in a line, all originally colored white.

Let L be the length of the longest continuous sub-segment of white unit squares. Let P be any prime that satisfies the condition that . The player can choose any P if it satisfies the conditions but if there is no value of P that does, then P is set to 1.

The current player then proceeds to choose any continuous sub-segment of white unit squares of length P and paint them black. The player who can’t make a move loses.

If both players play optimally and the first player starts, which player is going to win the game?

Input
The first line of input is T – the number of test cases.

Each test case contains a line with a single integer N (1 ≤ N ≤ 107).

Output
For each test case, output on a single line “first” (without quotes) if the first player would win the game, or “second” if the second would win.

Example
Input
2
2
5
Output
second
first

题意 ： 给出一行 1 * n 的格子，一开始全是白色的，你可以选择不大于 p <=[L / 2] (向上取整，L为当前连着的最大数量的白色格子)的质数（没有不大于 p 的质数时，p取 1）去填任意 p 个格子，问最后先手和后手，谁最后一个把格子填满

思路 ： 模拟几个数会发现，只用在 n 等于 2 或 3 时后手会赢，其余都是先手赢

AC代码：

#include<cstdio>#include<cmath>#include<map>#include<cstring>#include<algorithm>using namespace std;const int MAX = 1e5 + 10;typedef long long LL;int main(){    int T; scanf("%d",&T);    while(T--){        int n,a;        scanf("%d",&a);        if(a == 2 || a == 3) puts("second");        else puts("first");    }    return 0;}