Submission #1013567

#	Time	Username	Problem	Language	Result	Execution time	Memory
1013567		spacewalker	Ideal city (IOI12_city)	C++17	32 / 100	1070 ms	2908 KiB

city

#include <bits/stdc++.h>

using namespace std;

using ll = long long;
constexpr ll MOD = 1'000'000'000;

vector<pair<int, int>> dirs = {{-1, 0}, {1, 0}, {0, -1}, {0, 1}};

int DistanceSum(int N, int *X, int *Y) {
  // cerr << "!!! BRUTE SOLUTION " << endl;
  map<pair<int, int>, int> cell_index;
  for (int i = 0; i < N; ++i) cell_index[{X[i], Y[i]}] = i;
  vector<vector<int>> graph(N);
  for (int i = 0; i < N; ++i) {
    for (auto [dx, dy] : dirs) {
      int nx = X[i] + dx, ny = Y[i] + dy;
      auto possible_index = cell_index.find({nx, ny});
      if (possible_index != cell_index.end()) {
        graph[i].push_back(possible_index->second);
      }
    }
  }

  ll ans = 0;
  for (int i = 0; i < N; ++i) {
    vector<int> dist(N, -1);
    dist[i] = 0;
    queue<int> q;
    q.push(i);
    while (!q.empty()) {
      int cur = q.front(); q.pop();
      for (int nxt : graph[cur]) {
        if (dist[nxt] != -1) continue;
        dist[nxt] = dist[cur] + 1;
        q.push(nxt);
      }
    }
    ans += accumulate(dist.begin(), dist.end(), 0LL);
  }
  return ans / 2 % MOD;
}

• Subtask 1: 11 / 11
• Subtask 2: 21 / 21
• Subtask 3: 0 / 23
• Subtask 4: 0 / 45