HDU3364 Lanterns(求矩阵的秩)

求矩阵的秩，及判断有无解

#include<cstdio>
#include<iostream>
#include<cstdlib>
#include<cstring>
#include<string>
#include<algorithm>
#include<map>
#include<queue>
#include<vector>
#include<cmath>
#include<utility>
using namespace std;
typedef long long LL;
const int N = 60, INF = 0x3F3F3F3F;
const double eps = 1e-8;

template<typename T>
int gauss_jordan(T A[N][N], int n, int m){
    int i, c;
    for(i = 0, c = 0; i < n && c < m; i++, c++){
        int r = i;
        for(int j = i + 1; j < n; j++){
            if(A[j][c]){
                r = j;
                break;
            }
        }
        if(A[r][c] == 0){
            i--;
            continue;
        }
        if(r != i){
            for(int j = 0; j <= m; j++){
                swap(A[r][j], A[i][j]);
            }
        }
        for(int k = 0; k < n; k++){
            if(k != i && A[k][c]){
                for(int j = m; j >= c; j--){
                    A[k][j] ^= A[i][j];
                }
            }
        }
    }
    for(int j = i ; j < n; j++){
        if(A[j][m]){
            return -1;
        }
    }
    return i;
}

int a[N][N], b[N][N];
int main(){
    int t;
    cin>>t;
    for(int cas = 1; cas <= t; cas++){
        int n, m;
        scanf("%d %d", &n, &m);
        memset(b, 0, sizeof(b));
        for(int i = 0; i < m; i++){
            int cnt;
            scanf("%d", &cnt);
            while(cnt--){
                int v;
                scanf("%d", &v);
                v--;
                b[v][i] = 1;
            }
        }
        int q;
        scanf("%d", &q);
        printf("Case %d:\n", cas);
        while(q--){
            for(int i = 0; i < n; i++){
                for(int j = 0; j < m; j++){
                    a[i][j] = b[i][j];
                }
            }
            for(int i = 0; i < n; i++){
                scanf("%d", &a[i][m]);
            }
            int ans = gauss_jordan(a, n, m);
            if(ans == -1){
                printf("0\n");
            }else{
                printf("%I64d\n", 1ll << (m - ans));
            }

        }

    }

    return 0;
}