Submission #525585

#	Time	Username	Problem	Language	Result	Execution time	Memory
525585		Gurban	Commuter Pass (JOI18_commuter_pass)	C++17	100 / 100	319 ms	20716 KiB

commuter_pass

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

using ll = long long;

const int maxn=1e5+5;
int n,m,a[4];
bool vis[maxn];
ll dp[maxn];
ll dis[4][maxn],ans;
vector<int>v;
vector<pair<int,int>>E[maxn];

void f(int cp,int sg){
	for(int i = 1;i <= n;i++) dp[i] = 1e9;
	for(auto i : v){
		dp[i] = dis[cp][i];
		for(auto j : E[i]){
			if(dis[0][j.first] + j.second == dis[0][i] and j.second + dis[0][j.first] + dis[1][i] == dis[0][a[1]]) dp[i] = min(dp[i],dp[j.first]);
		}
		// if(dp[i] + dis[sg][i] == 0) cout<<i<<' '<<dis[0][i]<<' '<<dis[1][i]<<' '<<dis[2][i]<<' '<<dis[3][i]<<'\n';
		ans = min(ans,dp[i] + dis[sg][i]);
	}
}

int main(){
	ios::sync_with_stdio(false);
	cin.tie(0);

	cin >> n >> m >> a[0] >> a[1] >> a[2] >> a[3];
	for(int i = 1;i <= m;i++){
		int x,y,w; cin >> x >> y >> w;
		E[x].push_back({y,w});
		E[y].push_back({x,w});
	}

	for(int i = 0;i < 4;i++){
		for(int j = 1;j <= n;j++) dis[i][j] = 1e18,vis[j] = 0;
		dis[i][a[i]] = 0;
		priority_queue<pair<ll,int>>q;
		q.push({0,a[i]});
		while(!q.empty()){
			int x = q.top().second; q.pop();
			if(vis[x]) continue;
			if(i == 0) v.push_back(x);
			vis[x] = 1;
			for(auto j : E[x]){
				if(dis[i][j.first] > dis[i][x] + j.second){
					dis[i][j.first] = dis[i][x] + j.second;
					q.push({-dis[i][j.first],j.first});
				}
			}
		}
	}
	ans = dis[2][a[3]];
	// for(auto i : v) cout<<i<<' ';
	// cout<<'\n';
	// cout<<ans<<'\n';
	f(2,3);
	f(3,2);
	cout<<ans;
}

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