Submission #104681

#	Time	Username	Problem	Language	Result	Execution time	Memory
104681		WLZ	Paths (BOI18_paths)	C++17	100 / 100	1043 ms	268152 KiB

paths

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

int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  int n, m, k;
  cin >> n >> m >> k;
  vector<int> a(n + 1);
  for (int i = 1; i <= n; i++) {
    cin >> a[i];
    a[i]--;
  }
  vector< vector<int> > g(n + 1);
  for (int i = 0; i < m; i++) {
    int u, v;
    cin >> u >> v;
    g[u].push_back(v);
    g[v].push_back(u);
  }
  vector< vector< vector<long long> > > dp(k, vector< vector<long long> >(n + 1, vector<long long>(1 << k, 0)));
  for (int i = 1; i <= n; i++) {
    dp[0][i][1 << a[i]] = 1;
  }
  for (int i = 0; i < k - 1; i++) {
    for (int u = 1; u <= n; u++) {
      for (int mask = 0; mask < (1 << k); mask++) {
        if (dp[i][u][mask] == 0) {
          continue;
        }
        for (auto& v : g[u]) {
          if (mask & (1 << a[v])) {
            continue;
          }
          dp[i + 1][v][mask | (1 << a[v])] += dp[i][u][mask];
        }
      }
    }
  }
  long long ans = 0;
  for (int i = 1; i < k; i++) {
    for (int u = 1; u <= n; u++) {
      for (int mask = 0; mask < (1 << k); mask++) {
        ans += dp[i][u][mask];
      }
    }
  }
  cout << ans << '\n';
  return 0;
}

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