Submission #258102

#	Time	Username	Problem	Language	Result	Execution time	Memory
258102		maximath_1	Cities (BOI16_cities)	C++11	100 / 100	1254 ms	28200 KiB

cities

#include <iostream>
#include <vector>
#include <queue>
#include <algorithm>
#include <bitset>
using namespace std;
#define ll long long
const ll inf = 1e18 + 69;

int n, k, m;
vector<pair<int, int> > adj[100005];
ll dp[16][100005];
bitset<100005> vis;
int imp[5], rt;

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

	cin >> n >> k >> m;
	cin >> rt; k --;
	for(int i = 0; i < k; i ++) cin >> imp[i];
	for(int u, v, w, i = 0; i < m; i ++){
		cin >> u >> v >> w;
		adj[u].push_back({v, w});
		adj[v].push_back({u, w});
	}

	for(int i = 0; i < 16; i ++) for(int j = 1; j <= n; j ++){
		if(i == 0) dp[i][j] = 0;
		else dp[i][j] = inf;
	}

	for(int msk = 0; msk < (1 << k); msk ++){
		priority_queue<pair<ll, int>, vector<pair<ll, int> >, greater<pair<ll, int> > > pq;
		for(int i = 1; i <= n; i ++){
			for(int submsk = (msk - 1) & msk; submsk; submsk = (submsk - 1) & msk)
				dp[msk][i] = min(dp[msk][i], dp[submsk][i] + dp[submsk ^ msk][i]);
			vis[i] = 0;
			pq.push({dp[msk][i], i});
		}

		for(; !pq.empty();){
			int nw = pq.top().second; pq.pop();
			if(vis[nw]) continue;
			vis[nw] = 1;
			for(auto i : adj[nw]){
				int nx = i.first, wt = i.second;
				if(dp[msk][nx] > dp[msk][nw] + wt){
					dp[msk][nx] = dp[msk][nw] + wt;
					pq.push({dp[msk][nx], nx});
				}
			}
		}

		for(int i = 0; i < k; i ++)
			dp[msk | (1 << i)][imp[i]] = min(dp[msk | (1 << i)][imp[i]], dp[msk][imp[i]]);
	}

	cout << dp[(1 << k) - 1][rt] << endl;
	return 0;
}

• Subtask 1: 22 / 22
• Subtask 2: 14 / 14
• Subtask 3: 15 / 15
• Subtask 4: 23 / 23
• Subtask 5: 26 / 26