Submission #682046

#	Time	Username	Problem	Language	Result	Execution time	Memory
682046		kym	Commuter Pass (JOI18_commuter_pass)	C++14	16 / 100	366 ms	34008 KiB

commuter_pass

#include <bits/stdc++.h>
using namespace std;
#define int long long 
#define FOR(i,s,e) for(int i = s; i <= (int)e; ++i)
#define DEC(i,s,e) for(int i = s; i >= (int)e; --i)
#define IAMSPEED ios_base::sync_with_stdio(false); cin.tie(0);
#ifdef LOCAL
#define db(x) cerr << #x << "=" << x << "\n"
#define db2(x, y) cerr << #x << "=" << x << " , " << #y << "=" << y << "\n"
#define db3(a,b,c) cerr<<#a<<"="<<a<<","<<#b<<"="<<b<<","<<#c<<"="<<c<<"\n"
#define dbv(v) cerr << #v << ":"; for (auto ite : v) cerr << ite << ' '; cerr <<"\n"
#define dbvp(v) cerr << #v << ":"; for (auto ite : v) cerr << "{"  << ite.f << ',' << ite.s << "} "; cerr << "\n"
#define dba(a,ss,ee) cerr << #a << ":"; FOR(ite,ss,ee) cerr << a[ite] << ' '; cerr << "\n"
#define reach cerr << "LINE: " << __LINE__ << "\n";
#else
#define reach 
#define db(x)
#define db2(x,y)
#define db3(a,b,c)
#define dbv(v)
#define dbvp(v)
#define dba(a,ss,ee)
#endif
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
#define pb push_back
#define eb emplace_back
#define all(x) (x).begin(), (x).end()
#define f first 
#define s second
#define g0(x) get<0>(x)
#define g1(x) get<1>(x)
#define g2(x) get<2>(x)
#define g3(x) get<3>(x)
typedef pair <int, int> pi;
typedef tuple<int,int,int> ti3;
typedef tuple<int,int,int,int> ti4;
int rand(int a, int b) { return a + rng() % (b-a+1); }
const int MOD = 1e9 + 7;
const int inf = (int)1e9 + 500;
const long long oo = (long long)1e18 + 500;
template <typename T> bool chmax(T& a, const T b) { return a<b ? a = b, 1 : 0; }
template <typename T> bool chmin(T& a, const T b) { return a>b ? a = b, 1 : 0; }
const int MAXN = 200005;
int n,m;
int s,t;
int u,v;
vector<pi> adj[MAXN];
int dist[MAXN][4];
int D1[MAXN], Dn[MAXN];
struct edge {
	int u, v, c;
} E[MAXN];
typedef pair<int,pi> pii;
void dij(int source, int * dist) {
	FOR(i,0,n)dist[i]=oo;
	dist[source] = 0;
	priority_queue<pi,vector<pi>,greater<pi>> pq;
	pq.push({0, source});
	while(pq.size()) {
		pi c=pq.top(); pq.pop();
		int x=c.s, d=c.f;
		if(dist[x]!=d)continue;
		for(auto v:adj[x]) {
			int nd=v.s+d;
			int nx=v.f;
			if(dist[nx]>nd) {
				dist[nx]=nd;
				pq.push({nd,nx});
			}
		}
	}
}
int32_t main() 
{
	IAMSPEED
	cin >> n >> m;
	cin >> s >> t;
	cin >> u >> v;
	FOR(i,1,m){
		int a,b,c;cin>>a>>b>>c;
		E[i]={a,b,c};
		adj[a].pb({b,c});
		adj[b].pb({a,c});
	}
	dij(s,D1);
	dij(t,Dn);

	FOR(i,0,n)FOR(j,0,3)dist[i][j]=oo;
	priority_queue<pii,vector<pii>,greater<pii>>pq;

	dist[u][0]=0;
	pq.push({0,{u,0}}); // i haven't started anything yet. 
	while(pq.size()) {
		pii c=pq.top(); pq.pop();
		int d=c.f, x=c.s.f, y=c.s.s;
	
		if(dist[x][y]!=d)continue;
		for(auto v:adj[x]) {
			int nx=v.f;
			if(y == 1 || y == 0) { // increasing path
				bool on=(D1[t] == D1[x] + v.s + Dn[nx]); // this path is part of commuter pass
				if(on) {
					if(chmin(dist[nx][1],dist[x][y])) {
						pq.push({dist[nx][1], {nx, 1}});
					}
				}  

				if(y==0) {
					if(chmin(dist[nx][0],dist[x][y] + v.s)) {
						pq.push({dist[nx][0], {nx,0}});
					}
				} else {
					if(chmin(dist[nx][3], dist[x][y] + v.s)) {
						pq.push({dist[nx][3], {nx,3}});
					}
				}
				

			} else if(y == 0 || y==2){
				bool on=(Dn[s] == Dn[x] + v.s + D1[nx]);
				if(on) {
					if(chmin(dist[nx][2],dist[x][y])) {
						pq.push({dist[nx][2], {nx, 2}});
					}
				} 
				 {
					if(y==0){
						if(chmin(dist[nx][0],dist[x][y] + v.s)) {
							pq.push({dist[nx][0], {nx,0}});
						}
					} else {
						if(chmin(dist[nx][3],dist[x][y]+v.s)) {
							pq.push({dist[nx][3], {nx, 3}});
						}
					}
					
				}
			} else {
				if(chmin(dist[nx][y],dist[x][y] + v.s)) {
					pq.push({dist[nx][y], {nx,y}});
				}
			}
		}
	}
	cout << min({dist[v][0], dist[v][1], dist[v][2], dist[v][3]}) << '\n';

}

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