Submission #402960

#	Time	Username	Problem	Language	Result	Execution time	Memory
402960		rainboy	Crocodile's Underground City (IOI11_crocodile)	C11	100 / 100	597 ms	50996 KiB

crocodile

#include "crocodile.h"
#include <stdlib.h>
#include <string.h>

#define N	100000
#define INF	0x3f3f3f3f

int *ej[N], *ew[N], eo[N];

void append(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;
}

int dd1[N], dd2[N], iq[1 + N], pq[N], cnt;

int lt(int i, int j) {
	return dd2[i] < dd2[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;
}

int travel_plan(int n, int m, int ij[][2], int *ww, int k, int *ii) {
	int h, i, j;

	for (i = 0; i < n; i++) {
		ej[i] = (int *) malloc(2 * sizeof *ej[i]);
		ew[i] = (int *) malloc(2 * sizeof *ew[i]);
	}
	for (h = 0; h < m; h++) {
		i = ij[h][0], j = ij[h][1];
		append(i, j, ww[h]), append(j, i, ww[h]);
	}
	memset(dd1, 0x3f, n * sizeof *dd1), memset(dd2, 0x3f, n * sizeof *dd2);
	for (h = 0; h < k; h++) {
		i = ii[h];
		dd1[i] = dd2[i] = 0, pq_add_last(i);
	}
	while (cnt) {
		int o;

		i = pq_remove_first();
		if (i == 0)
			return dd2[i];
		for (o = eo[i]; o--; ) {
			int j = ej[i][o], w = ew[i][o], d = dd2[i] + w;

			if (dd1[j] > d) {
				if (dd2[j] == INF && dd1[j] != INF)
					pq_add_last(j);
				dd2[j] = dd1[j], dd1[j] = d, pq_up(j);
			} else if (dd2[j] > d) {
				if (dd2[j] == INF)
					pq_add_last(j);
				dd2[j] = d, pq_up(j);
			}
		}
	}
	return -1;
}

Compilation message (stderr)

crocodile.c: In function 'append':
crocodile.c:13:23: warning: suggest parentheses around '-' in operand of '&' [-Wparentheses]
   13 |  if (o >= 2 && (o & o - 1) == 0) {
      |                     ~~^~~

• Subtask 1: 46 / 46
• Subtask 2: 43 / 43
• Subtask 3: 11 / 11