Submission #689970

#	Time	Username	Problem	Language	Result	Execution time	Memory
689970		NK_	Paths (BOI18_paths)	C++17	100 / 100	600 ms	105504 KiB

paths

// Success consists of going from failure to failure without loss of enthusiasm
#include <bits/stdc++.h>

using namespace std;

#define nl '\n'

using ll = int64_t;

int main() {
	cin.tie(0)->sync_with_stdio(0);
	
	int N, M, K; cin >> N >> M >> K;

	vector<int> A(N); for(auto& x : A) { cin >> x; --x; }

	vector<vector<vector<int>>> adj(N, vector<vector<int>>(K));

	for(int i = 0; i < M; i++) {
		int u, v; cin >> u >> v; --u, --v;
		// cout << u << " " << v << nl;
		adj[u][A[v]].push_back(v);
		adj[v][A[u]].push_back(u);
	}

	vector<vector<ll>> dp(N, vector<ll>(1<<K, 0));

	for(int i = 0; i < N; i++) dp[i][1<<A[i]] = 1;

	int P2 = 1;
	ll ans = 0;
	for(int s = 1; s < (1<<K); s++) {
		if (P2 < s) P2 += P2;
		for(int u = 0; u < N; u++) if (dp[u][s] != 0) {
			if (s != P2) ans += dp[u][s];
			for(int b = 0; b < K; b++) if (((s >> b) & 1) ^ 1) {
				for(const auto &v : adj[u][b]) dp[v][s^(1<<b)] += dp[u][s];
			}
		}
	}
	cout << ans << nl;


    return 0;
}

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