2018 ACM-ICPC, Syrian Collegiate Programming Contest F - Pretests SOS dp

#include<bits/stdc++.h>
#define LL long long
#define fi first
#define se second
#define mk make_pair
#define PLL pair<LL, LL>
#define PLI pair<LL, int>
#define PII pair<int, int>
#define SZ(x) ((int)x.size())
#define ull unsigned long long
using namespace std;

const int N = 2e5 + ;
const int inf = 0x3f3f3f3f;
const LL INF = 0x3f3f3f3f3f3f3f3f;
const int mod = 1e9 + ;
const double eps = 1e-;
const double PI = acos(-);

int T, m, n, up, dp2[<<], dp[<<], pre[<<];
char s[];
vector<int> ans;

int main() {
//    freopen("tests.in", "r", stdin);
    scanf("%d", &T);
    while(T--) {
        ans.clear();
        scanf("%d%d", &m, &n);
        up =  << m;
        for(int i = ; i < up; i++) dp2[i] = , dp[i] = inf;
        for(int i = ; i < n; i++) {
            scanf("%s", s); int x = ;
            for(int j = ; j < m; j++)
                if(s[j] == '') x +=  << j;
            dp2[x]++;
        }
        for(int i = ; i < m; i++)
            for(int s = ; s < up; s++)
                if(s>>i&) dp2[s^(<<i)] += dp2[s];
        dp[] = ;
        for(int s = ; s < up; s++) {
            for(int i = ; i < m; i++) {
                if(s>>i&) continue;
                int nexs = s | (<<i);
                if(dp[s]+dp2[s] < dp[nexs]) {
                    dp[nexs] = dp[s]+dp2[s];
                    pre[nexs] = s;
                }
            }
        }
        int nows = up-, nexs;
        while(nows) {
            nexs = pre[nows];
            int xo = nexs ^ nows;
            for(int i = ; i < m; i++) {
                if(<<i == xo) {
                    ans.push_back(i+);
                    break;
                }
            }
            nows = nexs;
        }
        reverse(ans.begin(), ans.end());
        printf("%d\n", dp[up-]);
        for(int t : ans) printf("%d ", t);
        puts("");
    }
    return ;
}
/*
*/