Submission #1275307

#	Time	Username	Problem	Language	Result	Execution time	Memory
1275307		almaz	Commuter Pass (JOI18_commuter_pass)	C++20	0 / 100	2097 ms	327680 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
*/

int ans = INF;
vector <vector <int>> p;
map <pair<int,int> , int> mp;
vector <vector <pair<int,int>>> g;
int n;

void res(int i, vector <int> a, int s, int u, int v){
	if(i == s){
		// cout<<"here"<<endl;
		for(int j = 0;j < (int)a.size() - 1;j++){
			mp[{a[j] , a[j + 1]}] = 1;
			mp[{a[j + 1] , a[j]}] = 1;
		}
		// for(int j = 0;j < (int)a.size();j++){
			// cout<<a[j]<<' ';
		// }
		// cout<<endl;
		set <pair<int,int>> st;
		st.insert({0 , v});
		
		vector <int> cnt(n + 1, INF);
		cnt[v] = 0;
		
		while(!st.empty()){
			int x = st.begin() -> ss;
			st.erase(st.begin());
			// cout<<x<<endl;
			
			for(auto [j, c] : g[x]){
				int l = c;
				if(mp[{j , x}]){
					l = 0;
				}
				if(cnt[j] > cnt[x] + l){
					cnt[j] = cnt[x] + l;
					st.insert({cnt[j] , j});
				}
			}
		}
		for(int j = 0;j < (int)a.size() - 1;j++){
			mp[{a[j] , a[j + 1]}] = 0;
			mp[{a[j + 1] , a[j]}] = 0;
		}
		
		ans = min(ans, cnt[u]);
		return;
	}
	else{
		for(int j : p[i]){
			a.pb(j);
			res(j, a, s, u, v);
			a.pop_back(); 
		}
	}
}

void solve(){
	int m;
	cin >> n >> m;
	int s, t, u, v;
	cin >> s >> t >> u >> v;
	
	p.resize(n + 1);
	g.resize(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});
	}
	
	
	
	vector <int> cnt(n + 1, INF);
	cnt[s] = 0;
	
	set <pair<int,int>> st;
	st.insert({0 , s});
	
	while(!st.empty()){
		int x = st.begin() -> ss;
		st.erase(st.begin());
		
		for(auto [i, c] : g[x]){
			if(cnt[i] > cnt[x] + c){
				cnt[i] = cnt[x] + c;
				p[i].clear();
				p[i].pb(x);
				st.insert({cnt[i] , i});
			}
			else if(cnt[i] == cnt[x] + c){
				p[i].pb(x);
			}
		}
	}
	
	// for(int i = 1;i <= n;i++){
		// cout<< cnt[i] << ' ';
	// }
	// cout<<endl;
	
	// for(int i = 1;i <= n;i++){
		// cout<<i << ": ";
		// for(int j : p[i]){
			// cout<<j<<' ';
		// }
		// cout<<endl;
	// }
	
	vector <int> h;
	h.pb(t);
	res(t , h, s, u , v);
	
	
	cout<< ans <<endl;
}

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

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