题目

思路：

#include <bits/stdc++.h>
using namespace std;
#define int long long
#define pb push_back
#define fi first
#define se second
#define lson p << 1
#define rson p << 1 | 1
const int maxn = 1e6 + 5, inf = 1e18, maxm = 4e4 + 5, base = 37;
const int N = 1e6;const int mod = 1e9 + 7;
// const int mod = 998244353;
//const __int128 mod = 212370440130137957LL;
//  int a[1005][1005];
// bool vis[505][505];
// char s[2005][2005];
int n, m;
int a[maxn];// string s;struct Node{// int val, id;// bool operator<(const Node &u)const{//     return val < u.val;//!!!!!!!!!!!!!!!!!!// }int v, w;
};struct DSU{vector<int> fa;DSU(int n) : fa(n) {for(int i = 0; i < n; i++){fa[i] = i;}} int find(int x){if(x == fa[x]) return x;return fa[x] = find(fa[x]);}void merge(int x, int y){if(find(x) != find(y)){fa[find(x)] = find(y);}}
}; //long long ? maxn ? n? m?
void solve(){int res = 0;cin >> n >> m;vector<vector<int>> a(n + 5, vector<int>(m + 5));for(int i = 1; i <= n; i++){for(int j = 1; j <= m; j++){char ch;cin >> ch;a[i][j] = ch - '0';}}DSU d(2 * n + 5);for(int j = 1; j <= m / 2; j++){vector<int> vec[2];for(int i = 1; i <= n; i++){if(a[i][j]){vec[0].pb(i);}if(a[i][m - j + 1]){vec[1].pb(i);}}if(vec[0].size() + vec[1].size() >= 3){cout << 0 << '\n';return;}for(int x = 0; x < 2; x++){for(int y = 0; y < vec[x].size(); y++){for(int z = y + 1; z < vec[x].size(); z++){int u = vec[x][y], v = vec[x][z];d.merge(u + n, v);d.merge(u, v + n);}}}if(vec[0].size() && vec[1].size()){int u = vec[0][0], v = vec[1][0];d.merge(u, v);d.merge(u + n, v + n);}}if(m % 2 == 1){int j = (m + 1) / 2;vector<int> vec;for(int i = 1; i <= n; i++){if(a[i][j]){vec.pb(i);}}if(vec.size() >= 2){cout << 0 << '\n';return;}}for(int i = 1; i <= n; i++){if(d.find(i) == d.find(i + n)){cout << 0 << '\n';return;}}int cnt = 0;for(int i = 1; i <= 2 * n; i++){if(d.find(i) == i) cnt++;}cnt /= 2;res = 1;for(int i = 1; i <= cnt; i++){res = res * 2 % mod;}cout << res << '\n';
}   signed main(){ios::sync_with_stdio(0);cin.tie(0);cout << fixed << setprecision(9);int T = 1;cin >> T;while (T--){solve();}return 0;
}