Submission #473377

#	Time	Username	Problem	Language	Result	Execution time	Memory
473377		elgamalsalman	Paths (BOI18_paths)	C++14	100 / 100	511 ms	109732 KiB

paths

#include <bits/stdc++.h>

using namespace std;

typedef long long ll;
typedef vector<int> vi;
typedef vector<vi> vvi;

ll dp[350050][32];
int n, m, k, colours[350050];
vvi adj;

ll dfs(int u, int mask) {
  if (dp[u][mask] != -1) return dp[u][mask];
  //cerr << "// dfs(" << u << ", " << mask << ")\n";

  mask |= (1 << colours[u]);
  ll pathsCount = 0;
  for (int v : adj[u]) {
    if ((1 << colours[v]) & mask) continue;
    pathsCount += 1 + dfs(v, mask);
  }
  mask ^= (1 << colours[u]);

  dp[u][mask] = pathsCount;
  return dp[u][mask];
}

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

  cin >> n >> m >> k;
  adj.assign(n + 20, vi());
  for (int i = 0; i < n; i++) {
    cin >> colours[i];
    colours[i]--;
  }

  for (int i = 0; i < m; i++) {
    int a, b;
    cin >> a >> b;
    a--; b--;
    adj[a].push_back(b);
    adj[b].push_back(a);
  }

  memset(dp, -1, sizeof dp);
  ll ans = 0;
  for (int i = 0; i < n; i++) {
    ans += dfs(i, 0);
  }

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

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