https://cn.vjudge.net/problem/Gym-101147A
首先定义mex(minimal excludant)运算,这是施加于一个集合的运算,表示最小的不属于这个集合的非负整数。例如mex{0,1,2,4}=3、mex{2,3,5}=0、mex{}=0。
SG 定理:游戏的和的 SG 值是各个子游戏的 SG 值的 xor。
<tr1/unordered_map>
#include <unordered_map>
#include <cmath>
//#include<bits/stdc++.h>
using namespace std;
#define sfi(i) scanf("%d",&i)
#define sfl(i) scanf("%lld",&i)
#define sfs(i) scanf("%s",(i))
#define pri(i) printf("%d\n",i)
#define prl(i) printf("%I64d\n",i)
#define sff(i) scanf("%lf",&i)
#define ll long long
#define ull unsigned long long
#define uint unsigned int
#define mem(x,y) memset(x,y,sizeof(x))
#define INF 0x3f3f3f3f
#define inf 1e18
#define eps 1e-10
#define PI acos(-1.0)
#define lowbit(x) ((x)&(-x))
#define fl() printf("flag\n")
#define MOD(x) ((x%mod)+mod)%mod
#define endl '\n'
#define pb push_back
#define lson (rt<<1)
#define rson (rt<<1|1)
#define FAST_IO ios::sync_with_stdio(false);cin.tie(0);cout.tie(0)
template<typename T>inline void read(T &x)
{
x=0;
static int p;p=1;
static char c;c=getchar();
while(!isdigit(c)){if(c=='-')p=-1;c=getchar();}
while(isdigit(c)) {x=(x<<1)+(x<<3)+(c-48);c=getchar();}
x*=p;
}
//-----------------------------------------------
const int maxn=5e5+9;
const int mod=1e9+7;
int main()
{
//FAST_IO;
//freopen("input.txt","r",stdin);
freopen("powers.in","r",stdin);
int T;
cin>>T;
while(T--)
{
int g;
cin>>g;
int ans=0;
for(int i=1;i<=g;i++)
{
int b,n;
cin>>b>>n;
if(b&1)
{
if(n&1) ans^=1;
else ans^=0;
}
else
{
int yu=n%(b+1);
if(yu==b)
{
ans^=2;//sg 可以0||1
}
else
{
if(yu&1) ans^=1;
else ans^=0;
}
}
}
if(ans) cout<<1<<endl;
else cout<<2<<endl;
}
return 0;
}