Submission #945151

#	Time	Username	Problem	Language	Result	Execution time	Memory
945151		Xiaoyang	Commuter Pass (JOI18_commuter_pass)	C++17	15 / 100	2045 ms	52540 KiB

commuter_pass

#include <bits/stdc++.h>
using namespace std;
#pragma GCC optimize("O3,unroll-loops")
#pragma GCC target("avx2,bmi,bmi2,lzcnt,popcnt")
typedef long long ll;
 
#define fi first 
#define se second 
#define pll pair<ll,ll>
#define pb push_back
#define debug(x) cerr<<#x<<"="<<x<<endl;
#define MP make_pair
#define rep(i,a,b) for(ll i=a;i<b;i++)
#define SZ(x) (ll)x.size()
#define ALL(x) x.begin(),x.end()
#define endl "\n"
const ll inf=1e18;
ll lowbit(ll x){return x&(-x);}


const ll maxn=1e5+5;
map<pll,bool>mp;
vector<pll>alist[maxn];
ll st[maxn],uv[maxn];
ll n,m;
ll s,t;
ll u,v;

void dfs(ll uu){
	for(auto x:alist[uu]){
		if(st[x.se]>st[uu])continue;
		if(st[x.se]+x.fi==st[uu]){
			mp[MP(x.se,uu)]=1;
			mp[MP(uu,x.se)]=1;
			dfs(x.se);
		}
	}
}
int main(){
	ios::sync_with_stdio(0);
	cin.tie(0);
	ll n,m;cin>>n>>m;
	ll s,t;cin>>s>>t;
	ll u,v;cin>>u>>v;
	rep(i,0,m){
		ll a,b,c;cin>>a>>b>>c;
		alist[a].pb(MP(c,b));
		alist[b].pb(MP(c,a));
	}
	
	memset(st,63,sizeof st);
	st[s]=0;
	priority_queue<pll,vector<pll>,greater<pll>>q;
	q.push(MP(0ll,s));
	while(!q.empty()){
		auto uu=q.top();
		q.pop();
		if(uu.fi!=st[uu.se])continue;
		for(auto x:alist[uu.se]){
			if(uu.fi+x.fi<st[x.se]){
				st[x.se]=uu.fi+x.fi;
				q.push(MP(st[x.se],x.se));
			}
		}
	}
	dfs(t);
	
	//for(auto xx:mp)cout<<xx.fi.fi<<" "<<xx.fi.se<<endl;
	
	memset(uv,63,sizeof uv);
	uv[u]=0;
	while(!q.empty())q.pop();
	q.push(MP(0ll,u));
	while(!q.empty()){
		auto uu=q.top();
		q.pop();
		if(uu.fi!=uv[uu.se])continue;
		for(auto x:alist[uu.se]){
			if(mp[MP(x.se,uu.se)])x.fi=0;
			//debug(x.fi);
			//debug(x.se);
			//debug(uu.fi);
			if(uu.fi+x.fi<uv[x.se]){
				uv[x.se]=uu.fi+x.fi;
				q.push(MP(uv[x.se],x.se));
			}
		}
	}
	//rep(i,1,n+1)cout<<uv[i]<<" ";
	//cout<<endl;
	cout<<uv[v]<<endl;
	return 0;
}

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