Submission #1273653

#	Time	Username	Problem	Language	Result	Execution time	Memory
1273653		kaiboy	Commuter Pass (JOI18_commuter_pass)	C++20	100 / 100	262 ms	14372 KiB

commuter_pass

#include <algorithm>
#include <iostream>

using namespace std;

const       int   N = 100000;
const long long INF = 0x3f3f3f3f3f3f3f3fLL;

int *ej[N], *ew[N], eo[N], pq[N], iq[N + 1], pq_cnt, qu[N];
long long dd_s[N], dd_t[N], dd_u[N], dd_v[N], *dd;

void append(int i, int j, int w) {
	int o = eo[i]++;
	if (!o) {
		ej[i] = (int *) malloc(sizeof *ej[i]);
		ew[i] = (int *) malloc(sizeof *ew[i]);
	} else if (!(o & o - 1)) {
		ej[i] = (int *) realloc(ej[i], (o << 1) * sizeof *ej[i]);
		ew[i] = (int *) realloc(ew[i], (o << 1) * sizeof *ew[i]);
	}
	ej[i][o] = j;
	ew[i][o] = w;
}

bool lt(int i, int j) {
	return dd[i] < dd[j];
}

int p2(int p) {
	return (p <<= 1) > pq_cnt ? 0 : p ^ (p < pq_cnt && lt(iq[p ^ 1], iq[p]));
}

void pq_up(int i) {
	int j, p, q;
	for (p = pq[i]; (q = p >> 1) && lt(i, j = iq[q]); p = q)
		iq[pq[j] = p] = j;
	iq[pq[i] = p] = i;
}

void pq_dn(int i) {
	int j, p, q;
	for (p = pq[i]; (q = p2(p)) && lt(j = iq[q], i); p = q)
		iq[pq[j] = p] = j;
	iq[pq[i] = p] = i;
}

void pq_add_last(int i) {
	iq[pq[i] = ++pq_cnt] = i;
}

int pq_remove_first() {
	int i = iq[1], j = iq[pq_cnt--];
	if (i != j)
		pq[j] = 1, pq_dn(j);
	pq[i] = 0;
	return i;
}

void dijkstra(int n, int s) {
	for (int i = 0; i < n; i++)
		dd[i] = INF;
	dd[s] = 0, pq_add_last(s);
	for (int h = 0; h < n; h++) {
		int i = qu[h] = pq_remove_first();
		for (int o = 0; o < eo[i]; o++) {
			int j = ej[i][o], w = ew[i][o];
			long long d = dd[i] + w;
			if (dd[j] > d) {
				if (dd[j] == INF)
					pq_add_last(j);
				dd[j] = d, pq_up(j);
			}
		}
	}
}

int main() {
	ios_base::sync_with_stdio(false), cin.tie(NULL);
	int n, m; cin >> n >> m;
	int s, t; cin >> s >> t, s--, t--;
	int u, v; cin >> u >> v, u--, v--;
	while (m--) {
		int i, j, w; cin >> i >> j >> w, i--, j--;
		append(i, j, w), append(j, i, w);
	}
	dd = dd_t, dijkstra(n, t);
	dd = dd_u, dijkstra(n, u);
	dd = dd_v, dijkstra(n, v);
	dd = dd_s, dijkstra(n, s);
	long long ans = dd_u[v];
	for (int h = 0; h < n; h++) {
		int i = qu[h];
		if (dd_s[i] + dd_t[i] == dd_s[t]) {
			long long d_u = dd_u[i], d_v = dd_v[i];
			for (int o = 0; o < eo[i]; o++) {
				int j = ej[i][o], w = ew[i][o];
				if (dd_s[j] + w == dd_s[i]) {
					d_u = min(d_u, dd_u[j]);
					d_v = min(d_v, dd_v[j]);
				}
			}
			ans = min(ans, min(d_u + dd_v[i], dd_u[i] + d_v));
			dd_u[i] = d_u, dd_v[i] = d_v;
		}
	}
	cout << ans << '\n';
	return 0;
}

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