Submission #990502

#	Time	Username	Problem	Language	Result	Execution time	Memory
990502		tch1cherin	Red-blue table (IZhO19_stones)	C++17	100 / 100	20 ms	2396 KiB

stones

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

vector<string> build(int N, int M, int h, int w) {
  vector<string> A(N, string(M, 0));
  if (h > 0) {
    assert(M % 2 == 0);
    string rot(N, '-');
    fill(rot.begin(), rot.begin() + (N + 1) / 2, '+');
    for (int j = 0; j < M; j++) {
      for (int i = 0; i < N; i++) {
        A[i][j] = rot[i];
      }
      rotate(rot.begin(), rot.begin() + (N + 1) / 2, rot.end());
    }
  } else {
    assert(N % 2 == 0);
    string rot(M, '+');
    fill(rot.begin(), rot.begin() + (M + 1) / 2, '-');
    for (int i = 0; i < N; i++) {
      for (int j = 0; j < M; j++) {
        A[i][j] = rot[j];
      }
      rotate(rot.begin(), rot.begin() + (M + 1) / 2, rot.end());
    }
  }
  return A;
}

int main() {
  cin.tie(nullptr)->sync_with_stdio(false);
  int T;
  cin >> T;
  while (T--) {
    int N, M;
    cin >> N >> M;
    if (N <= 2 || M <= 2) {
      cout << max(N, M) << "\n";
      for (int i = 0; i < N; i++) {
        cout << string(M, "-+"[N > M]) << "\n";
      }
    } else {
      int h, w;
      if (N % 2 && M % 2) {
        h = w = 1;
      } else if (N % 2 != M % 2) {
        if (N % 2 ? N * 2 <= M + 4 : M * 2 <= N + 4)  {
          if (N % 2) {
            h = 2, w = 0;
          } else {
            h = 0, w = 2;
          }
        } else {
          if (N % 2) {
            h = 1, w = 2;
          } else {
            h = 2, w = 1;
          }
        }
      } else {
        if (min(N, M) * 2 <= max(N, M) + 6) {
          if (N > M) {
            h = 0, w = 3;
          } else {
            h = 3, w = 0;
          }
        } else {
          h = w = 2;
        }
      }
      vector<string> A = build(N - h, M - w, h, w);
      cout << N + M - w - h << "\n";
      for (int i = 0; i < N; i++, cout << "\n") {
        for (int j = 0; j < M; j++) {
          cout << (i < N - h && j < M - w ? A[i][j] : "-+"[i < N - h]);
        }
      }
    }
  }
}

• Subtask 1: 17 / 17
• Subtask 2: 10 / 10
• Subtask 3: 16 / 16
• Subtask 4: 11 / 11
• Subtask 5: 15 / 15
• Subtask 6: 31 / 31