Submission #817977

#	Time	Username	Problem	Language	Result	Execution time	Memory
817977		OAleksa	Commuter Pass (JOI18_commuter_pass)	C++14	100 / 100	323 ms	29628 KiB

commuter_pass

#include <bits/stdc++.h>
//#include "factories.h"
//#include "wall.h"
#define f first
#define s second
#define int long long
using namespace std; 
const int maxn = 1e5 + 69;
vector<pair<int, int>> g[maxn];
int n, m, s, t, u, v;
const int inf = 1e18;
vector<int> d(maxn, inf);
vector<int> ds(maxn, inf), dt(maxn, inf);
vector<int> du(maxn, inf), dv(maxn, inf);
vector<int> in(maxn, inf), out(maxn, inf);
signed main()
{
	ios_base::sync_with_stdio(false);
	cin.tie(0);
	cout.tie(0);
	int tt = 1;
	//cin >> tt;
	while(tt--) {
		cin >> n >> m >> s >> t >> u >> v;
		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});
		}
		ds[s] = du[u] = dv[v] = dt[t] = d[s] = 0;
		priority_queue<pair<int, int>> pq;
		pq.push({0, s});
		while(!pq.empty()) {
			auto u = pq.top();
			pq.pop();
			for(auto v : g[u.s]) {
				if(ds[v.f] <= ds[u.s] + v.s)
					continue;
				ds[v.f] = ds[u.s] + v.s;
				pq.push({-ds[v.f], v.f});
			}
		}
		pq.push({0, t});
		while(!pq.empty()) {
			auto u = pq.top();
			pq.pop();
			for(auto v : g[u.s]) {
				if(dt[v.f] <= dt[u.s] + v.s)
					continue;
				dt[v.f] = dt[u.s] + v.s;
				pq.push({-dt[v.f], v.f});
			}
		}
		pq.push({0, u});
		while(!pq.empty()) {
			auto u = pq.top();
			pq.pop();
			for(auto v : g[u.s]) {
				if(du[v.f] <= du[u.s] + v.s)
					continue;
				du[v.f] = du[u.s] + v.s;
				pq.push({-du[v.f], v.f});
			}
		}
		pq.push({0, v});
		while(!pq.empty()) {
			auto u = pq.top();
			pq.pop();
			for(auto v : g[u.s]) {
				if(dv[v.f] <= dv[u.s] + v.s)
					continue;
				dv[v.f] = dv[u.s] + v.s;
				pq.push({-dv[v.f], v.f});
			}
		}
		int ans = du[v];
		for(int i = 1;i <= n;i++)
			in[i] = out[i] = inf;
		function<void(int)> dfs1 = [&](int v) {
			if(in[v] != inf || ds[v] + dt[v] != ds[t])
				return;
			in[v] = du[v];
			for(auto u : g[v]) {
				if(ds[u.f] == ds[v] + u.s) {
					dfs1(u.f);
					in[v] = min(in[u.f], in[v]);
				}
			}
			ans = min(ans, in[v] + dv[v]);
		};
		function<void(int)> dfs2 = [&](int v) {
			if(in[v] != inf || ds[v] + dt[v] != ds[t])
				return;
			in[v] = du[v];
			for(auto u : g[v]) {
				if(dt[u.f] == dt[v] + u.s) {
					dfs2(u.f);
					in[v] = min(in[u.f], in[v]);
				}
			}
			ans = min(ans, in[v] + dv[v]);
		};
		dfs1(s);
		for(int i = 1;i <= n;i++)
			in[i] = inf;
		dfs2(t);
		cout << ans;
	}
   return 0;
}

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