提出 #53848220

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ソースコード 拡げる

#include <bits/stdc++.h>
using namespace std;

#define FOR(i, a, n) for (int i = a; i < (int)n; i++)
#define rep(i, n) FOR(i, 0, n)
#define all(x) begin(x), end(x)

using lli = long long int;

void print_yn(bool b) {
  cout << ((b) ? "Yes" : "No") << endl;
}

template <typename ForwardIterator>
void print_vec(ForwardIterator first, ForwardIterator last) {
  while (first != last) {
    cout << *(first++);
    cout << (first == last ? "\n" : " ");
  }
}

int N, T;
int A[4000001];
int R[2001];
int C[2001];
int D[3];

int main() {
  cin >> N >> T;
  rep(i, T) { cin >> A[i]; A[i]--; }
  rep(i, N) { R[i] = C[i] = N; }
  rep(i, 2) { D[i] = N; }

  rep(i, T) {
    int r = A[i] / N;
    int c = A[i] % N;
    R[r]--;
    C[c]--;

    bool d1 = r == c;
    bool d2 = r == (N-c-1);
    if (d1) { D[0]--; }
    if (d2) { D[1]--; }

    if (R[r] == 0 || C[c] == 0 || D[0] == 0 || D[1] == 0) {
      cout << (i+1) << endl;
      return 0;
    }
  }

  cout << -1 << endl;
  return 0;
}

提出情報

ジャッジ結果