取石子（斐波那契博弈）

题意：http://acm.hdu.edu.cn/showproblem.php?pid=2516

1堆石子有n个,两人轮流取.先取者第1次可以取任意多个，但不能全部取完.以后每次取的石子数不能超过上次取子数的2倍。取完者胜.先取者负输出"Second win".先取者胜输出"First win".

#include<iostream>
using namespace std;
int main() {
    int n, i,flag=1;
    int a[1000] = { 0 };
    a[0] = 0; a[1] = 1; a[2] = 1;
    for (i = 3; i < 1000; i++) {
        a[i] = a[i - 1] + a[i - 2];
    }
    while (cin >> n) {
        if (n == 0)
            exit(0);
        else {
            for (i = 3; i < 1000; i++) {
                if (n == a[i]) {
                    cout << "Second win" << endl;
                    flag = 0;
                    break;
                }
            }
            if (flag == 1) {
                cout << "First win" << endl;
            }
            else {
                flag = 1;
            }
        }
    }
    return 0;
}