Chess

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经典博弈问题，sg函数的应用，因为m<=20，用状态压缩存储就好了。
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队友代码

#include <bits/stdc++.h>using namespace std;int a[2000002];int p[50];int b[50];int s[50];int T;int n, m;int x;int ans;void makefull(){    p[1] = 1;    for (int i = 2; i < 25; i++)        p[i] = 2*p[i-1] + 1;}int main(){    for (int i = 0; i < 1048576; i++)        a[i] = -1;    a[0] = 0;    makefull();    for (int i = 1; i <= 20; i++)        a[p[i]] = 0;    for (int i = 1; i < 1048576; i++)        if (a[i] == -1)        {            for (int j = 0; j < 20; j++)                s[j] = 0;            int t = i, len;            for (len = 1; t > 0; len++)            {                b[len] = t & 1;                t>>=1;            }            for (int ii = 1; ii < len; ii++)            {                if (b[ii] == 0)                {                    for (int jj = ii+1; jj < len; jj++)                    {                        int yuan = (i%(1<<jj))>>ii;                        if ((yuan) == p[jj-ii])                        {                               int pos = i-(yuan<<ii)+(yuan << (ii-1));                            s[a[pos]] = 1;                        }                        else break;                    }                }            }            for (a[i] = 0; s[a[i]]; a[i]++);        }    scanf("%d", &T);    while (T--)    {        scanf("%d", &n);        ans = 0;        for (int i = 1; i <= n; i++)        {            scanf("%d", &m);            x = 0;            for (int j = 1; j <= m; j++)            {                int xx;                scanf("%d", &xx);                xx = 20 - xx;                x += (1<<xx);            }            ans ^= a[x];        }        if (ans > 0) puts("YES");            else puts("NO");    }    return 0;}