Submission #430805

#	Time	Username	Problem	Language	Result	Execution time	Memory
430805		wind_reaper	Paths (BOI18_paths)	C++17	100 / 100	760 ms	97300 KiB

paths

#include <bits/stdc++.h>
/*
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
*/

using namespace std;
// using namespace __gnu_pbds;
using namespace chrono;

// mt19937 rng((int) std::chrono::steady_clock::now().time_since_epoch().count());
/*
template <class T> using ordered_set = tree <T, null_type, less <T>, rb_tree_tag, tree_order_statistics_node_update>;
*/

//***************** CONSTANTS *****************

const int MXN = 300001;

//***************** GLOBAL VARIABLES *****************

int N, M, K;
vector<int> g[MXN];
int a[MXN];
int64_t dp[MXN][32];

//***************** AUXILIARY STRUCTS *****************



//***************** MAIN BODY *****************


void solve(){
	cin >> N >> M >> K;

	for(int i = 1; i <= N; i++){
		cin >> a[i];
		--a[i];
	}

	for(int i = 0; i < M; i++){
		int u, v;
		cin >> u >> v;
		g[u].push_back(v);
		g[v].push_back(u);
	}

	int64_t ans = 0;

	for(int mask = 1; mask < (1 << K); mask++){
		for(int u = 1; u <= N; u++){
			if(!(mask & (1 << a[u])))
				continue;
			if(__builtin_popcount(mask) == 1) dp[u][mask]++;
			for(int v : g[u])
				if(a[u] != a[v])
					dp[u][mask] += dp[v][mask ^ (1 << a[u])];

			ans += dp[u][mask]; 
		}
	}

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

//***************** *****************

int32_t main(){
	ios_base::sync_with_stdio(NULL);
	cin.tie(NULL);

	#ifdef LOCAL
		auto begin = high_resolution_clock::now();
	#endif

	int tc = 1;
	// cin >> tc; 
	for (int t = 0; t < tc; t++)
		solve();

	#ifdef LOCAL 
		auto end = high_resolution_clock::now();
		cout << fixed << setprecision(4);
		cout << "Execution Time: " << duration_cast<duration<double>>(end - begin).count() << "seconds" << endl;
	#endif

	return 0;
}

/*
If code gives a WA, check for the following : 
1. I/O format

2. Are you clearing all global variables in between tests if multitests are a thing

3. Can you definitively prove the logic
*/

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