Submission #332105

#	Time	Username	Problem	Language	Result	Execution time	Memory
332105		soroush	Commuter Pass (JOI18_commuter_pass)	C++14	100 / 100	500 ms	43740 KiB

commuter_pass

//*
//#pragma GCC optimize("O2")
//#pragma GCC optimize("Ofast")
//#pragma GCC optimize("unroll-loops")
//#pragma GCC target("avx,avx2,sse,sse2,fma")
//*/
#include <bits/stdc++.h>

using namespace std;

typedef long long ll;
#define int ll
typedef long double ld;
typedef pair<int  ,int > pii;

mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());

const ll maxn  = 2e5 + 10;
const ll mod =1e9+7;
const ld PI = acos((ld)-1);

#define pb push_back
#define endl '\n'
#define dokme(x) cout << x , exit(0)
#define migmig ios::sync_with_stdio(false),cin.tie(0),cout.tie(0)
#define ms(x , y) memset(x , y , sizeof x)
ll pw(ll a, ll b, ll md = mod){ll res = 1;while(b){if(b&1){res=(a*res)%md;}a=(a*a)%md;b>>=1;}return(res);}

struct tr{
	int u , w;
	tr(int a , int b):
		u(a) , w(b){}
	friend bool operator < (tr a  , tr b){
		if(a.w == b.w)return(a.u < b.u);
		return(a.w > b.w);
	}
};

int n , m;
vector < tr > adj[maxn];
int s , t;
int a , b;
vector < int > ds , dt;
priority_queue < tr > st;
bool mark[maxn];

#define insert push
#define erase pop

void djk(int v, vector < int > &dist){
	ms(mark , 0);
	for(int i = 0 ; i <= n ; i ++)
		dist.pb(1e18);
	dist[v] = 0;
	st.insert({v , dist[v]});
	while(!st.empty()){
		auto vw = (st.top());
		auto v = vw.u;
		st.erase();
		if(mark[v])continue;
		mark[v] = 1;
		for(auto uw : adj[v])
			if(dist[uw.u] > dist[v] + uw.w)
				dist[uw.u] = dist[v] + uw.w,
				st.insert({uw.u , dist[uw.u]});
	}
}

vector < int > du , dv;

bool sp(int u , int v , int w){
	return((ds[u] + dt[v] + w == ds[t]));
}

int mn[maxn] , mnr[maxn];
int ans = 1e18;

vector < int > in[maxn] , out[maxn];

int d[maxn];

vector < int > topo;

void dfs(int v){
	topo.pb(v);
	mark[v] = 1;
	for(auto u : out[v]){
		d[u] -- ;
		if(d[u] == 0)
			dfs(u);
	}
}

int32_t main(){
    migmig;
	cin >> n >> m;
	cin >> s >> t;
	cin >> a >> b;
	for(int i = 1;  i <= m ; i ++){
		int u , v , w;
		cin >> u >> v >> w;
		adj[u].pb({v , w});
		adj[v].pb({u , w});
	}
	djk(s , ds);
	djk(t , dt);
	djk(a , du);
	djk(b , dv);
	for(int v = 1 ; v <= n ; v ++){
		for(auto uw : adj[v]){
			auto u = uw.u;
			auto w = uw.w;
			if(sp(v , u , w))in[u].pb(v) , out[v].pb(u) , d[u] ++ ;
		}
	}
	ms(mark , 0);
	for(int i = 1; i <= n ; i ++)if(d[i] == 0 and !mark[i])dfs(i);
	for(int i = 1; i <= n ; i ++)mn[i] = 1e18 , mnr[i] = 1e18;
	for(auto v : topo){
		mn[v] = du[v];
		for(auto u : in[v])
			mn[v] = min(mn[v] , mn[u]);
	}
	reverse(topo.begin() , topo.end());
	for(auto v : topo){
		mnr[v] = du[v];
		for(auto u : out[v])
			mnr[v] = min(mnr[v] , mnr[u]);
	}
	for(int i = 1 ; i <= n ; i ++)mn[i] = min(mn[i] , mnr[i]);
	for(int i = 1 ; i <= n ; i ++)
		ans = min(ans , dv[i] + mn[i]);
	cout << ans;
    return(0);
}

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