Submission #1086670

#	Time	Username	Problem	Language	Result	Execution time	Memory
1086670		khoile25108	Commuter Pass (JOI18_commuter_pass)	C++14	100 / 100	297 ms	31612 KiB

commuter_pass

#include <bits/stdc++.h>
using namespace std;
#define faster ios_base::sync_with_stdio(0); cin.tie(0);
#define FOR(i,a,b) for(int i = a; i <= b; i++)
#define FOD(i,a,b) for(int i = a; i >= b; i--)
#define int long long
#define fi first
#define se second
#define pb push_back
#define ll long long
#define ull unsigned long long
#define lcm(a,b) (a*b)/__gcd(a,b)
#define ii pair<int,int>
#define iii pair<int,pair<int,int>>
#define iv pair<pair<int,int>,pair<int,int>>

const int inf = 1e9;
const ll INF = 1e18;
const int mod = 1e9 + 7;
const int N = 1e5 + 105;

const int dx[] = {-1,0,1,0};
const int dy[] = {0,1,0,-1};
const int dxx[] = {-1,-1,0,1,1,1,0,-1};
const int dyy[] = {0,1,1,1,0,-1,-1,-1};

int n, m, S, T, U, V, ans;
vector<ii> g[N];
int du[N], dv[N], dp[N][2], ds[N];

void dijk1(int beg, int d[])
{
	priority_queue<ii,vector<ii>,greater<ii>> pq;
	FOR(i,1,n) d[i] = INF;
	d[beg] = 0;
	pq.push({0,beg});
	while(!pq.empty())
	{
		int u = pq.top().se;
		int cost = pq.top().fi;
		pq.pop();
		if(cost > d[u]) 
			continue;
		for(ii H : g[u])
		{
			int v = H.fi;
			int l = H.se;
			if(d[v] > d[u] + l)
			{
				d[v] = d[u] + l;
				pq.push({d[v],v});
			}
		}
	}
}

void dijk2(int beg, int des)
{
	priority_queue<iii,vector<iii>,greater<iii>> pq;
	pq.push({0,{0,beg}});
	FOR(i,0,n) 
	{
		dp[i][0] = INF;
		dp[i][1] = INF;
		ds[i] = INF;
	}
	while(!pq.empty())
	{
		int u = pq.top().se.se;
		int par = pq.top().se.fi;
		int cost = pq.top().fi;
		pq.pop();
		if(ds[u] == INF)
		{
			ds[u] = cost;
			dp[u][0] = min(dp[par][0], du[u]);
			dp[u][1] = min(dp[par][1], dv[u]);
			for(ii H : g[u])
				pq.push({cost + H.se, {u, H.fi}});
		}
		else if(ds[u] == cost)
		{
			if(min(dp[par][0], du[u]) + min(dp[par][1], dv[u]) <= dp[u][0] + dp[u][1])
			{
				dp[u][0] = min(dp[par][0], du[u]);
				dp[u][1] = min(dp[par][1], dv[u]);			
			}
		}
	}
	ans = min(ans, dp[des][0] + dp[des][1]);
}

void solve()
{
	dijk1(U,du);
	dijk1(V,dv);

	ans = du[V];

	dijk2(S,T);
	dijk2(T,S);

	cout << ans;
}

void input()
{
	//freopen("TEST.INP", "r", stdin);
	//freopen("TEST.OUT", "w", stdout);
	cin >> n >> m >> S >> T >> U >> V;
	FOR(i,1,m)
	{
		int u, v, w;
		cin >> u >> v >> w;
		g[u].pb({v,w});
		g[v].pb({u,w});
	}
}

signed main()
{
	faster
	input();
	solve();
}

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