Submission #934433

#	Time	Username	Problem	Language	Result	Execution time	Memory
934433		ind1v	Paths (BOI18_paths)	C++11	100 / 100	218 ms	73812 KiB

paths

#include <bits/stdc++.h>

using namespace std;

const int N = 3e5 + 5;
const int K = 6;

int n, m, k;
int c[N];
int a[N], b[N];
vector<int> g[N];
int adj[N][K], adjadj[N][K][K];

int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  cin >> n >> m >> k;
  for (int i = 1; i <= n; i++) {
    cin >> c[i];
  }
  for (int i = 1; i <= m; i++) {
    cin >> a[i] >> b[i];
    adj[a[i]][c[b[i]]]++;
    adj[b[i]][c[a[i]]]++;
    g[a[i]].emplace_back(b[i]);
    g[b[i]].emplace_back(a[i]);
  }
  for (int i = 1; i <= n; i++) {
    for (int &j : g[i]) {
      for (int cc = 1; cc <= k; cc++) {
        adjadj[i][min(c[j], cc)][max(c[j], cc)] += adj[j][cc];
      }
    }
  }
  long long ans = 0;
  if (2 <= k) {
    for (int i = 1; i <= m; i++) {
      ans += 2 * (c[a[i]] != c[b[i]]);
    }
  }
  if (3 <= k) {
    for (int i = 1; i <= n; i++) {
      for (int c1 = 1; c1 <= k; c1++) {
        for (int c2 = 1; c2 <= k; c2++) {
          if (c1 != c2 && c1 != c[i] && c2 != c[i]) {
            ans += 1LL * adj[i][c1] * adj[i][c2];
          }
        }
      }
    }
  }
  if (4 <= k) {
    for (int i = 1; i <= m; i++) {
      if (c[a[i]] == c[b[i]]) {
        continue;
      }
      for (int c1 = 1; c1 <= k; c1++) {
        for (int c2 = 1; c2 <= k; c2++) {
          if (c1 != c2 && c1 != c[a[i]] && c1 != c[b[i]] && c2 != c[a[i]] && c2 != c[b[i]]) {
            ans += 2LL * adj[a[i]][c1] * adj[b[i]][c2];
          }
        }
      }
    }
  }
  if (5 <= k) {
    for (int i = 1; i <= n; i++) {
      vector<int> col;
      for (int j = 1; j <= k; j++) {
        if (j != c[i]) {
          col.emplace_back(j);
        }
      }
      sort(col.begin(), col.end());
      do {
        if (col[0] < col[1] && col[2] < col[3]) {
          ans += adjadj[i][col[0]][col[1]] * adjadj[i][col[2]][col[3]];
        }
      } while (next_permutation(col.begin(), col.end()));
    }
  }
  cout << ans << '\n';
  return 0;
}

• Subtask 1: 23 / 23
• Subtask 2: 20 / 20
• Subtask 3: 27 / 27
• Subtask 4: 30 / 30