hdu 1848 博弈

比较简单的sg函数的应用，将每一堆的sg值求出，则总游戏的sg值为3个异或起来。

#include <iostream>
#include <cstring>
#include <cstdio>
using namespace std;

const int N = 1001;
const int M = 20;
int sg[N];
int f[M];
bool mex[M];

void init()
{
    f[0] = 1;
    f[1] = 2;
    for ( int i = 2; i < M; i++ )
    {
        f[i] = f[i - 1] + f[i - 2];
    }
}

void get()
{
    init();
    for ( int i = 0; i < N; i++ )
    {
        memset( mex, 0, sizeof(mex) );
        for ( int j = 0; i >= f[j]; j++ )
        {
            mex[sg[i - f[j]]] = true;
        }
        for ( int j = 0; j < M; j++ )
        {
            if ( !mex[j] )
            {
                sg[i] = j;
                break;
            }
        }
    }
}

int main ()
{
    get();
    int a, b, c;
    while ( scanf("%d%d%d", &a, &b, &c) != EOF )
    {
        if ( !a && !b && !c ) break;
        if ( sg[a] ^ sg[b] ^ sg[c] )
        {
            puts("Fibo");
        }
        else
        {
            puts("Nacci");
        }
    }
    return 0;
}