Submission #535753

#	Time	Username	Problem	Language	Result	Execution time	Memory
535753		abc864197532	Olympic Bus (JOI20_ho_t4)	C++17	0 / 100	416 ms	2444 KiB

ho_t4

#include <bits/stdc++.h>
using namespace std;
#define lli long long int
#define mp make_pair
#define eb emplace_back
#define pb push_back
#define pii pair<int,int>
#define X first
#define Y second
#define all(x) x.begin(), x.end()
void abc() {cout << endl;}
template <typename T, typename ...U> void abc(T i, U ...j) {
	cout << i << ' ', abc(j...);
}
template <typename T> void printv(T l, T r) {
	for (; l != r; ++l)
		cout << *l << " \n"[l + 1 == r];
}
#ifdef Doludu
#define test(x...) abc("[" + string(#x) + "]", x)
#define owo freopen("input.txt", "r", stdin), freopen("output.txt", "w", stdout)
#else
#define test(x...) void(0)
#define owo ios::sync_with_stdio(false), cin.tie(0)
#endif
const int N = 205, M = 500001;

array <int, 4> E[M];

lli dis[N][N][N]; // dis[i][j][k] -> from i to k, forbid j
vector <int> adj[N];
lli dis2[N][N];

void build(int s, int forbid, int n) {
	for (int i = 0; i < n; ++i) {
		dis[s][forbid][i] = 1 << 30;
	}
	dis[s][forbid][s] = 0;
	if (s == forbid)
		return;
	priority_queue <pii, vector <pii>, greater <pii>> pq;
	pq.emplace(0, s);
	while (!pq.empty()) {
		int d, v; tie(d, v) = pq.top(); pq.pop();
		if (d < dis[s][forbid][v])
			continue;
		for (int id : adj[v]) {
			int u = E[id][0] ^ E[id][1] ^ v;
			if (u == forbid)
				continue;
			if (dis[s][forbid][u] > d + E[id][2])
				dis[s][forbid][u] = d + E[id][2], pq.emplace(dis[s][forbid][u], u);
		}
	}
}

int main () {
	owo;
	int n, m;
	cin >> n >> m;
	for (int i = 0; i < n; ++i) for (int j = 0; j < n; ++j)
		dis2[i][j] = 1 << 30;
	for (int i = 0; i < n; ++i)
		dis2[i][i] = 0;
	for (int i = 0, u, v, c, d; i < m; ++i) {
		cin >> u >> v >> c >> d, --u, --v;
		E[i] = {u, v, c, d};
		adj[u].pb(i);
		dis2[u][v] = min(dis2[u][v], 1ll * c);
	}
	for (int k = 0; k < n; ++k) for (int i = 0; i < n; ++i) for (int j = 0; j < n; ++j)
		dis2[i][j] = min(dis2[i][j], dis2[i][k] + dis2[k][j]);
	for (int i = 0; i < n; ++i) {
		build(0, i, n);
		build(n - 1, i, n);
	}
	lli ans = dis2[0][n - 1] * 2;
	for (int i = 0; i < m; ++i) {
		int u = E[i][0], v = E[i][1];
		ans = min(ans, E[i][3] + min(dis[0][u][v] + E[i][2] + dis[n - 1][v][u], dis2[0][n - 1]) + min(dis[n - 1][u][v] + E[i][2] + dis[0][v][u], dis2[n - 1][0]));
	}
	cout << (ans >= (1ll << 30) ? -1 : ans);
}

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