Submission #1275236

#	Time	Username	Problem	Language	Result	Execution time	Memory
1275236		almaz	Commuter Pass (JOI18_commuter_pass)	C++20	15 / 100	568 ms	43880 KiB

commuter_pass

#include <bits/stdc++.h>
using namespace std;

#define int long long
// #define endl '\n'
#define ff first
#define ss second
#define pb push_back
#define all(a) a.begin(), a.end()
#define rall(a) a.rbegin(), a.rend()
#define ar array

const int MOD = 1e9 + 7,INF = 1e18, N = 2e5 + 5;
/*
5 2
1 2 2
2 3 2
3 4 2
4 5 2

*/

void solve(){
	int n , m;
	cin >> n >> m;
	int s , t , u , v;
	cin >> s >> t >> u >> v;
	
	vector <vector <pair<int,int>>> g(n + 1);
	
	for(int i = 0;i < m;i++){
		int a , b , c;
		cin >> a >> b >> c;
		
		g[a].pb({b , c});
		g[b].pb({a , c});
	}
	map <pair<int,int> , int> mp;
{
	set <pair<int,int>> q;
	q.insert({0 , s});

	vector <int> cnt(n + 1, INF);
	cnt[s] = 0;
	
	vector <int> p(n + 1);
	p[s] = -1;
	
	while(!q.empty()){
		int x = q.begin() -> ss;
		q.erase(q.begin());
		
		for(auto [i , c] : g[x]){
			if(cnt[i] > cnt[x] + c){
				cnt[i] = cnt[x] + c;
				p[i] = x;
				q.insert({cnt[i] , i});
			}
		}
	}
	// for(int i = 1;i <= n;i++){
		// cout<<cnt[i]<<' ';
	// }
	// cout<<endl;
	// for(int i = 1;i <= n;i++){
		// cout<<p[i]<<' ';
	// }
	// cout<<endl;
	vector <int> pr;
	while(p[t] != -1){
		pr.pb(t);
		t = p[t];
		if(t == 0){
			break;
		}
	}
	pr.pb(s);
	
	
	for(int i = 0;i < (int)pr.size() - 1;i++){
		mp[{pr[i] , pr[i + 1]}] = 1;
		mp[{pr[i + 1], pr[i]}] = 1;
	}
}
	set <pair<int,int>> q;
	q.insert({0 , u});
	
	vector <int> cnt(n + 1, INF);
	cnt[u] = 0;
	
	while(!q.empty()){
		int x = q.begin() -> ss;
		q.erase(q.begin());
		// cout<<x<<endl;
		for(auto [i , c] : g[x]){
			int l = c;
			if(mp[{i , x}]){
				l = 0;
			}
			if(cnt[i] > cnt[x] + l){
				cnt[i] = cnt[x] + l;
				q.insert({cnt[i], i});
			}
		}
	}
	
	cout<<cnt[v]<<endl;
}

signed main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    int ti = 1;
    while (ti--) {
		solve();
    }
}

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