Submission #1286637

#	Time	Username	Problem	Language	Result	Execution time	Memory
1286637		SmuggingSpun	Paths (BOI18_paths)	C++20	100 / 100	328 ms	66332 KiB

paths

#include<bits/stdc++.h>
#define taskname "C"
using namespace std;
typedef long long ll;
int main(){
	ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
	if(fopen(taskname".inp", "r")){
		freopen(taskname".inp", "r", stdin);
	}
	int n, m, k;
	cin >> n >> m >> k;
	vector<vector<ll>>f(n + 1, vector<ll>(1 << k, 0LL));
	vector<int>c(n + 1);
	for(int i = 1; i <= n; i++){
		cin >> c[i];
		f[i][1 << --c[i]] = 1;
	}
	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);
	}
	for(int mask = 1; mask < (1 << k); mask++){
		for(int u = 1; u <= n; u++){
			for(int& v : g[u]){
				if((mask >> c[v] & 1) == 0){
					f[v][mask | (1 << c[v])] += f[u][mask];
				}
			}
		}
	}
	ll ans = 0;
	for(int i = 1; i <= n; i++){
		ans += accumulate(f[i].begin(), f[i].end(), 0LL);
	}
	cout << ans - n;
}

Compilation message (stderr)

paths.cpp: In function 'int main()':
paths.cpp:8:24: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
    8 |                 freopen(taskname".inp", "r", stdin);
      |                 ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~

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