Submission #301822

#	Time	Username	Problem	Language	Result	Execution time	Memory
301822		pit4h	Commuter Pass (JOI18_commuter_pass)	C++14	100 / 100	703 ms	53848 KiB

commuter_pass

#include<bits/stdc++.h>
#define st first
#define nd second
#define mp make_pair
#define pb push_back
#ifndef LOCAL
#define cerr if(0)cerr
#endif
using namespace std;
using ll = long long;
using ld = long double;
using pii = pair<int, int>;
using vi = vector<int>;
const ll INF = 1e16+1;
void dijkstra(int s, vector<vector<pii>>& g, vector<ll>& d) {
	int n = g.size()-1;
	vector<bool> vis(n+1);
	priority_queue<pair<ll, int>> Q;
	d[s] = 0;
	Q.push({d[s], s});
	while(Q.size()) {
		int cur = Q.top().nd;
		Q.pop();
		if(vis[cur]) continue;
		vis[cur] = 1;
		for(auto nxt: g[cur]) {
			if(!vis[nxt.st] && d[nxt.st] > d[cur] + nxt.nd) {
				d[nxt.st] = d[cur] + nxt.nd;
				Q.push({-d[nxt.st], nxt.st});
			}
		}
	}
}
int main() {
	ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
	int n, m; cin>>n>>m;
	int s, t; cin>>s>>t;
	int u, v; cin>>u>>v;
	vector<vector<pii>> g(n+1);
	for(int i=0; i<m; ++i) {
		int a, b, c;
		cin>>a>>b>>c;
		g[a].push_back({b, c});
		g[b].push_back({a, c});
	}
	vector<ll> d_s(n+1, INF), d_t(n+1, INF);
	dijkstra(s, g, d_s);
	dijkstra(t, g, d_t);
	auto G = g;
	for(int i=n+1; i<=3*n; ++i) {
		G.push_back({});
	}
	for(int i=1; i<=n; ++i) {
		for(auto edge: g[i]) {
			int j = edge.st, w = edge.nd;
			G[i+2*n].push_back({j+2*n, w});
			if(d_s[i] + w + d_t[j] == d_s[t]) {
				G[i+n].push_back({j+n, 0});		
			}
			else {
				G[i+n].push_back({j+2*n, w});
			}
		}
	}
	for(int i=1; i<=n; ++i) {
		G[i].push_back({i+n, 0});
		G[i+n].push_back({i+2*n, 0});
	}
	vector<ll> d(3*n+1, INF);
	auto D = d;
	dijkstra(u, G, d);
	dijkstra(v, G, D);
	cout<<min(d[v+2*n], D[u+2*n]);
}

• Subtask 1: 16 / 16
• Subtask 2: 15 / 15
• Subtask 3: 24 / 24
• Subtask 4: 45 / 45