Submission #331578

#	Time	Username	Problem	Language	Result	Execution time	Memory
331578		syy	Olympic Bus (JOI20_ho_t4)	C++17	0 / 100	83 ms	6764 KiB

ho_t4

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef long double ld;
#define FOR(i, a, b) for(ll i = (ll)a; i <= (ll)b; i++)
#define DEC(i, a, b) for(ll i = (ll)a; i >= (ll)b; i--)
typedef pair<ll, ll> pi;
typedef pair<pi, ll> pii;
typedef pair<ll, pi> ipi;
typedef pair<pi, pi> pipi;
#define f first
#define s second
typedef vector<ll> vi;
typedef vector<pi> vpi;
typedef vector<pii> vpii;
#define pb push_back
#define pf push_front
#define all(v) v.begin(), v.end()
#define size(v) (ll) v.size()
#define disc(v) sort(all(v)); v.resize(unique(all(v)) - v.begin());
#define INF (ll) 1e9 + 100
#define LLINF (ll) 1e15
#define fastio ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0)
#define sandybridge __attribute__((optimize("Ofast"), target("arch=sandybridge")))
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());    //can be used by calling rng() or shuffle(A, A+n, rng)
inline ll rand(ll x, ll y) { ++y; return (rng() % (y-x)) + x; } //inclusivesss

ll n, m, a, b, c, d, dist[2][205], ndist[2][205], ans, path[2][205];
pipi edge[50005];
vpii adj[205], radj[205];
priority_queue<pi, vpi, greater<pi>> pq;

void setpath() {
	FOR(i, 1, n) dist[0][i] = LLINF;
	dist[0][1] = 0;
	pq.push(pi(0, 1));
	while (!pq.empty()) {
		auto [d, x] = pq.top(); pq.pop();
		if (d > dist[0][x]) continue;
		for (auto [t, idx]:adj[x]) {
			auto [it, nd] = t;
			if (dist[0][it] > d + nd) {
				dist[0][it] = d + nd;
				path[0][it] = idx;
				pq.push(pi(d + nd, it));
			}
		}
	}
	
	FOR(i, 1, n) dist[1][i] = LLINF;
	dist[1][n] = 0;
	pq.push(pi(0, n));
	while (!pq.empty()) {
		auto [d, x] = pq.top(); pq.pop();
		if (d > dist[1][x]) continue;
		for (auto [t, idx]:adj[x]) {
			auto [it, nd] = t;
			if (dist[1][it] > d + nd) {
				dist[1][it] = d + nd;
				path[1][it] = idx;
				pq.push(pi(d + nd, it));
			}
		}
	}
}

void dijkstra(bool b, ll flip) {
	FOR(i, 1, n) ndist[b][i] = LLINF;
	dist[b][(b ? n : 1)] = 0;
	pq.push(pi(0, (b ? n : 1)));
	while (!pq.empty()) {
		auto [d, x] = pq.top(); pq.pop();
		if (d > ndist[b][x]) continue;
		for (auto [t, idx]:adj[x]) {
			auto [it, nd] = t;
			if (idx == flip) continue;
			if (ndist[b][it] > d + nd) {
				ndist[b][it] = d + nd;
				pq.push(pi(d + nd, it));
			}
		}
		if (x == edge[flip].f.s) {
			ll it = edge[flip].f.f, nd = edge[flip].s.f;
			if (ndist[b][it] > d + nd) {
				ndist[b][it] = d + nd;
				pq.push(pi(d + nd, it));
			}
		}
	}
}

int main() {
	fastio; cin >> n >> m;
	FOR(i, 1, m) {
		cin >> a >> b >> c >> d;
		adj[a].pb(pii(pi(b, c), i));
		radj[b].pb(pii(pi(a, c), i));
		edge[i] = pipi(pi(a, b), pi(c, d));
	}
	setpath();
	ans = dist[0][n] + dist[1][1];
	FOR(i, 1, m) {
		auto [t, tt] = edge[i];
		auto [a, b] = t;
		auto [c, d] = tt;
		ll res = d;
		if (path[0][b] == i) {
			dijkstra(0, i);
			res += ndist[0][n];
		} else res += min(dist[0][n], dist[0][b] + c + dist[1][a]);
		if (path[1][b] == i) {
			dijkstra(1, i);
			res += ndist[1][1];
		} else res += min(dist[1][1], dist[1][b] + c + dist[0][a]);
		ans = min(ans, res);
	}
	cout << (ans >= LLINF ? -1 : ans);
}

• Subtask 1: 0 / 5
• Subtask 2: 0 / 11
• Subtask 3: 0 / 21
• Subtask 4: 0 / 63