HDOJ1846博弈论之SG函数

题目链接：http://acm.hdu.edu.cn/showproblem.php?pid=1846

代码：

#include<bits/stdc++.h>
using namespace std;
typedef unsigned int ui;
typedef long long ll;
typedef unsigned long long ull;
#define pf printf
#define mem(a,b) memset(a,b,sizeof(a))
#define prime1 1e9+7
#define prime2 1e9+9
#define pi 3.14159265
#define lson l,mid,rt<<1
#define rson mid+1,r,rt<<1|1
#define scand(x) scanf("%llf",&x) 
#define f(i,a,b) for(int i=a;i<=b;i++)
#define scan(a) scanf("%d",&a)
#define mp(a,b) make_pair((a),(b))
#define P pair<int,int>
#define dbg(args) cout<<#args<<":"<<args<<endl;
#define inf 0x7ffffff
inline int read(){
    int ans=0,w=1;
    char ch=getchar();
    while(!isdigit(ch)){if(ch=='-')w=-1;ch=getchar();}
    while(isdigit(ch))ans=(ans<<3)+(ans<<1)+ch-'0',ch=getchar();
    return ans*w;
}
int n,m,t;
const int maxn=1005;
const ll mod=10000;
int sg[maxn],s[maxn];
void getSG(){
    mem(sg,0);
    for(int i=1;i<=n;i++){
        mem(s,0);
        for(int j=1;j<=m&&i-j>=0;j++){
            s[sg[i-j]]=1;//i的后继结点放到s中 
        }
        for(int j=0;j<=n;j++){
            if(!s[j]){sg[i]=j;break;}
        } 
    }
}
int main()
{
//    freopen("input.txt","r",stdin);
//    freopen("output.txt","w",stdout);
    std::ios::sync_with_stdio(false);
    t=read();
    while(t--){
        n=read(),m=read();
        getSG();
        if(sg[n])cout<<"first\n";
        else cout<<"second\n";
    }
}