Submission #705560

#	Time	Username	Problem	Language	Result	Execution time	Memory
705560		rainboy	Commuter Pass (JOI18_commuter_pass)	C11	100 / 100	502 ms	59832 KiB

commuter_pass

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#define N	100000
#define N_	(N * 4)
#define INF	0x3f3f3f3f3f3f3f3fLL

int *ej[N], *ew[N], eo[N], *ej_[N_], *ew_[N_], eo_[N_];

void append(int **ej, int **ew, int *eo, int i, int j, int w) {
	int o = eo[i]++;

	if (o >= 2 && (o & o - 1) == 0) {
		ej[i] = (int *) realloc(ej[i], o * 2 * sizeof *ej[i]);
		ew[i] = (int *) realloc(ew[i], o * 2 * sizeof *ew[i]);
	}
	ej[i][o] = j, ew[i][o] = w;
}

long long *dd_; int iq[N_ + 1], pq[N_], cnt;

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

int p2(int p) {
	return (p *= 2) > cnt ? 0 : (p < cnt && lt(iq[p + 1], iq[p]) ? p + 1 : p);
}

void pq_up(int i) {
	int p, q, j;

	for (p = pq[i]; (q = p / 2) && lt(i, j = iq[q]); p = q)
		iq[pq[j] = p] = j;
	iq[pq[i] = p] = i;
}

void pq_dn(int i) {
	int p, q, j;

	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] = ++cnt] = i;
}

int pq_remove_first() {
	int i = iq[1], j = iq[cnt--];

	if (j != i)
		pq[j] = 1, pq_dn(j);
	pq[i] = 0;
	return i;
}

void dijkstra(int **ej, int **ew, int *eo, long long *dd, int n, int s) {
	int i, o;

	dd_ = dd;
	memset(dd, 0x3f, n * sizeof *dd);
	memset(pq, 0, n * sizeof *pq), cnt = 0;
	dd[s] = 0, pq_add_last(s);
	while (cnt) {
		i = pq_remove_first();
		for (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() {
	static long long dds[N], ddt[N], dd[N_];
	int n, n_, m, s, t, u, v, i, j, w, o;

	scanf("%d%d%d%d%d%d", &n, &m, &s, &t, &u, &v), n_ = n * 4, s--, t--, u--, v--;
	for (i = 0; i < n; i++) {
		ej[i] = (int *) malloc(2 * sizeof *ej[i]);
		ew[i] = (int *) malloc(2 * sizeof *ew[i]);
	}
	while (m--) {
		scanf("%d%d%d", &i, &j, &w), i--, j--;
		append(ej, ew, eo, i, j, w);
		append(ej, ew, eo, j, i, w);
	}
	dijkstra(ej, ew, eo, dds, n, s);
	dijkstra(ej, ew, eo, ddt, n, t);
	for (i = 0; i < n_; i++) {
		ej_[i] = (int *) malloc(2 * sizeof *ej_[i]);
		ew_[i] = (int *) malloc(2 * sizeof *ew_[i]);
	}
	for (i = 0; i < n; i++) {
		append(ej_, ew_, eo_, i << 2 | 0, i << 2 | 1, 0);
		append(ej_, ew_, eo_, i << 2 | 0, i << 2 | 2, 0);
		append(ej_, ew_, eo_, i << 2 | 1, i << 2 | 3, 0);
		append(ej_, ew_, eo_, i << 2 | 2, i << 2 | 3, 0);
	}
	for (i = 0; i < n; i++)
		for (o = eo[i]; o--; ) {
			j = ej[i][o], w = ew[i][o];
			append(ej_, ew_, eo_, i << 2 | 0, j << 2 | 0, w);
			append(ej_, ew_, eo_, i << 2 | 3, j << 2 | 3, w);
			if (dds[i] + w + ddt[j] == dds[t])
				append(ej_, ew_, eo_, i << 2 | 1, j << 2 | 1, 0);
			if (dds[j] + w + ddt[i] == dds[t])
				append(ej_, ew_, eo_, i << 2 | 2, j << 2 | 2, 0);
		}
	dijkstra(ej_, ew_, eo_, dd, n_, u << 2 | 0);
	printf("%lld\n", dd[v << 2 | 3]);
	return 0;
}

Compilation message (stderr)

commuter_pass.c: In function 'append':
commuter_pass.c:14:23: warning: suggest parentheses around '-' in operand of '&' [-Wparentheses]
   14 |  if (o >= 2 && (o & o - 1) == 0) {
      |                     ~~^~~
commuter_pass.c: In function 'main':
commuter_pass.c:84:2: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
   84 |  scanf("%d%d%d%d%d%d", &n, &m, &s, &t, &u, &v), n_ = n * 4, s--, t--, u--, v--;
      |  ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
commuter_pass.c:90:3: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
   90 |   scanf("%d%d%d", &i, &j, &w), i--, j--;
      |   ^~~~~~~~~~~~~~~~~~~~~~~~~~~

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