Submission #551541

#	Time	Username	Problem	Language	Result	Execution time	Memory
551541		CyberSleeper	Commuter Pass (JOI18_commuter_pass)	C++17	100 / 100	365 ms	26048 KiB

commuter_pass

#include <bits/stdc++.h>
#define fastio      ios_base::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL)
#define debug(x)    cout << "Line " << __LINE__ << ", " << #x << " is " << x << endl
#define all(x)      x.begin(), x.end()
#define fi          first
#define se          second
#define mp          make_pair
#define pb          push_back
#define ll          long long
#define ull         unsigned long long
#define pll         pair<ll, ll>
#define pii         pair<int, int>
#define ld          long double
#define nl          endl
#define tb          '\t'
#define sp          ' '
#define sqr(x)      (x)*(x)
#define arr3        array<int, 3>
using namespace std;
 
const int MX=100005, MOD=1000000007, BLOCK=160, INF=2e9+7, LG=62;
const ll INFF=1000000000000000007;
const ld ERR=1e-6, pi=3.14159265358979323846;
 
int N, M, S, T, U, V, st[4];
ll dist[4][MX], ans=INFF, vis[2][MX];
vector<pll> adj[MX];

bool valid(int x, int y, ll v=0){
	return (dist[0][x]+v+dist[1][y]==dist[0][T]);
}
ll DP(int x, int dir){
	ll &ret=vis[dir][x];
	if(ret==-1){
		ret=dist[3][x];
		for(pll i:adj[x]){
			if(dir){
				if(valid(x, i.fi, i.se))
					ret=min(ret, DP(i.fi, dir));
			}else{
				if(valid(i.fi, x, i.se))
					ret=min(ret, DP(i.fi, dir));
			}
		}
	}
	return ret;
}
 
int main(){
    fastio;
	memset(vis, -1, sizeof(vis));
    cin >> N >> M >> S >> T >> U >> V;
	st[0]=S;
	st[1]=T;
	st[2]=U;
	st[3]=V;
	for(int i=0, u, v, w; i<M; i++){
		cin >> u >> v >> w;
		adj[u].pb({v, w});
		adj[v].pb({u, w});
	}
	for(int ii=0; ii<4; ii++){
		priority_queue<pll, vector<pll>, greater<pll>> PQ;
		PQ.push({0, st[ii]});
		for(int i=0; i<=N; i++)
			dist[ii][i]=INFF;
		dist[ii][st[ii]]=0;
		while(PQ.size()){
			ll idx=PQ.top().se, cost=PQ.top().fi;
			PQ.pop();
			if(cost>dist[ii][idx])
				continue;
			for(pll i:adj[idx]){
				if(cost+i.se<dist[ii][i.fi]){
					dist[ii][i.fi]=cost+i.se;
					PQ.push({dist[ii][i.fi], i.fi});
				}
			}
		}
	}
	ans=dist[2][V];
	vis[0][V]=vis[1][V]=0;
	for(int i=1; i<=N; i++){
		if(valid(i, i)){
			ans=min(ans, dist[2][i]+min(DP(i, 1), DP(i, 0)));
		}
	}
	cout << ans << nl;
}

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