제출 #387386

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
387386		rama_pang	IOI 바이러스 (JOI21_fever)	C++17	37 / 100	5074 ms	6212 KiB

fever

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

using lint = long long;
const lint inf = 1e18;

// Direction list:
// 0 = positive X
// 1 = positive Y
// 2 = negative X
// 3 = negative Y

int Solve(int N, vector<int> X, vector<int> Y, vector<int> D) {
  vector<vector<array<int, 4>>> adj(4, vector<array<int, 4>>(3));
  // (D value, Hash X, Hash Y, comparator)

  adj[0][0] = {3, 1, -1, 1};
  adj[0][1] = {2, 0, 2, 1};
  adj[0][2] = {1, 1, 1, 1};

  adj[1][0] = {2, 1, -1, 1};
  adj[1][1] = {3, 2, 0, 1};
  adj[1][2] = {0, 1, 1, 0};

  adj[2][0] = {1, 1, -1, 0};
  adj[2][1] = {0, 0, 2, 0};
  adj[2][2] = {3, 1, 1, 0};

  adj[3][0] = {0, 1, -1, 0};
  adj[3][1] = {1, 2, 0, 0};
  adj[3][2] = {2, 1, 1, 1};

  const auto Intersect = [&](int u, int v) {
    for (auto ar : adj[D[u]]) {
      if (D[v] == ar[0] &&
          X[u] * ar[1] + Y[u] * ar[2] == X[v] * ar[1] + Y[v] * ar[2] &&
          int(pair(X[u], Y[u]) < pair(X[v], Y[v])) == ar[3]) {
        return (abs(X[u] - X[v]) + abs(Y[u] - Y[v])) / 2;
      }
    }
    return -1;
  };

  vector<lint> dist(N, inf);
  dist[0] = 0;
  vector<int> done(N);
  for (int rep = 0; rep < N; rep++) {
    int u = -1;
    for (int i = 0; i < N; i++) if (!done[i]) {
      if (u == -1 || dist[u] > dist[i]) u = i;
    }
    if (dist[u] == inf) break;
    done[u] = 1;
    for (int v = 0; v < N; v++) {
      lint t = Intersect(u, v);
      if (t >= dist[u]) {
        dist[v] = min(dist[v], t);
      }
    }
  }

  return N - count(begin(dist), end(dist), inf);
}

vector<int> Direction(int N, vector<int> X, vector<int> Y) {
  vector<int> D(N);
  D[0] = 0;
  for (int i = 1; i < N; i++) {
    if (abs(X[i]) == abs(Y[i])) {
      if (X[i] > 0 && Y[i] > 0) {
        D[i] = 3;
      } else if (X[i] > 0 && Y[i] < 0) {
        D[i] = 1;
      } else {
        D[i] = 0;
      }
    } else {
      if (X[i] >= 0 && Y[i] >= 0) {
        if (abs(X[i]) > abs(Y[i])) {
          D[i] = 2;
        } else {
          D[i] = 3;
        }
      } else if (X[i] <= 0 && Y[i] >= 0) {
        if (abs(X[i]) > abs(Y[i])) {
          D[i] = 0;
        } else {
          D[i] = 3;
        }
      } else if (X[i] <= 0 && Y[i] <= 0) {
        if (abs(X[i]) > abs(Y[i])) {
          D[i] = 0;
        } else {
          D[i] = 1;
        }
      } else if (X[i] >= 0 && Y[i] <= 0) {
        if (abs(X[i]) > abs(Y[i])) {
          D[i] = 2;
        } else {
          D[i] = 1;
        }
      }
    }
  }

  return D;
}

int main() {
  ios::sync_with_stdio(0);
  cin.tie(0);

  int N;
  cin >> N;

  vector<int> X(N), Y(N);
  for (int i = 0; i < N; i++) {
    cin >> X[i] >> Y[i];
    X[i] *= 2; Y[i] *= 2;
  }

  for (int i = N - 1; i >= 0; i--) { // Initial person at (0, 0)
    X[i] -= X[0];
    Y[i] -= Y[0];
  }

  int ans = 0;
  for (int d = 0; d < 4; d++) {
    ans = max(ans, Solve(N, X, Y, Direction(N, X, Y)));
    for (int i = 0; i < N; i++) {
      tie(X[i], Y[i]) = pair(-Y[i], X[i]);
    }
  }

  cout << ans << '\n';
  return 0;
}

• Subtask 1: 5 / 5
• Subtask 2: 8 / 8
• Subtask 3: 6 / 6
• Subtask 4: 6 / 6
• Subtask 5: 12 / 12
• Subtask 6: 0 / 32
• Subtask 7: 0 / 31