[SDOI 2010]外星千足虫

#include <bits/stdc++.h>
using namespace std;
const int N = 1005;

int n, m, tot;
string s;
bitset<N> A[N];

void insert(bitset<N> S) {
    for (int i = 0; i < n; i++)
        if (S[i]) {
            if (A[i].any()) S ^= A[i];
            else {A[i] = S; ++tot; break; }
        }
}
void work() {
    scanf("%d%d", &n, &m);
    if (n > m) {puts("Cannot Determine"); return; }
    for (int i = 1; i <= m; i++) {
        cin >> s; bitset<N> S(s);
        cin >> s; if (s[0] == '1') S.flip(n);
        insert(S); if (tot == n) {printf("%d\n", i); break; }
    }
    if (tot < n) {puts("Cannot Determine"); return; }
    for (int i = n-1; i >= 0; i--)
        for (int j = i-1; j >= 0; j--)
            if (A[j][i]) A[j] ^= A[i];
    for (int i = n-1; i >= 0; i--) puts(A[i][n] ? "?y7M#" : "Earth");
}
int main() {work(); return 0; }