Submission #765937

#	Time	Username	Problem	Language	Result	Execution time	Memory
765937		OrazB	Commuter Pass (JOI18_commuter_pass)	C++14	0 / 100	2083 ms	19688 KiB

commuter_pass

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#include <functional>
using namespace __gnu_pbds;
using namespace std;
typedef tree<int, null_type, less<int>, rb_tree_tag,
             tree_order_statistics_node_update>
    ordered_set;
//Dijkstra->set
//set.find_by_order(x) x-position value
//set.order_of_key(x) number of strictly less elements don't need *set.??
#define N 100005
#define wr cout << "Continue debugging\n";
#define all(x) (x).begin(), (x).end()
#define ll long long int
#define pii pair <ll, ll>
#define pb push_back
#define ff first
#define ss second

int n, m, s, t, u, v;
vector<pii> E[N];

void dijk(int x, vector<ll>&dis){
	priority_queue<pii> q; q.push({0, x});
	dis[x] = 0;
	while(!q.empty()){
		int x = q.top().ss;
		q.pop();
		for (auto i : E[x]){
			if (dis[i.ff] > dis[x]+i.ss){
				dis[i.ff] = dis[x]+i.ss;
				q.push({-dis[i.ff], i.ff});
			}
		}
	}
}

int main ()
{
	ios::sync_with_stdio(false);
	cin.tie(0);
	cin >> n >> m >> s >> t >> u >> v;
	while(m--){
		int x, y, w;
		cin >> x >> y >> w;
		E[x].pb({y, w});
		E[y].pb({x, w});
	}
	vector<ll> disu(n+1, 1e18), disv(n+1, 1e18), diss(n+1, 1e18);
	dijk(v, disv);
	ll l = 0, r = 1e18, ans = -1;
	while(l <= r){
		ll md = (l+r)/2;
		vector<ll> dis(n+1, 1e18);
		vector<int> can(n+1, 0);
		priority_queue<pii> q; q.push({0, s});
		dis[s] = 0;
		while(!q.empty()){
			int x = q.top().ss;
			q.pop();
			if (disv[x] <= md) can[x] = 1;
			for (auto i : E[x]){
				if (dis[i.ff] > dis[x]+i.ss){
					dis[i.ff] = dis[x]+i.ss;
					can[i.ff] = can[x];
					q.push({-dis[i.ff], i.ff});
				}else if (dis[i.ff] == dis[x]+i.ss) can[i.ff] |= can[x];
			}
		}
		if (can[t]){
			ans = md;
			r = md - 1;
		}else l = md + 1;
	}
	cout << ans << '\n';
}		

• Subtask 1: 0 / 16
• Subtask 2: 0 / 15
• Subtask 3: 0 / 24
• Subtask 4: 0 / 45