Submission #768778

#	Time	Username	Problem	Language	Result	Execution time	Memory
768778		rainboy	Evacuation plan (IZhO18_plan)	C11	100 / 100	357 ms	30704 KiB

plan

#include <stdio.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 dd[N], 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;
}

int ds[N], ww[N];

int find(int i) {
	return ds[i] < 0 ? i : find(ds[i]);
}

void join(int i, int j, int w) {
	i = find(i);
	j = find(j);
	if (i == j)
		return;
	if (ds[i] > ds[j])
		ds[i] = j, ww[i] = w;
	else {
		if (ds[i] == ds[j])
			ds[i]--;
		ds[j] = i, ww[j] = w;
	}
}

int query(int i, int j) {
	int w = INF;

	while (i != j)
		if (ww[i] > ww[j])
			w = ww[i], i = ds[i];
		else
			w = ww[j], j = ds[j];
	return w;
}

int main() {
	static int ii[N];
	static char active[N];
	int n, m, k, q, h, i, j, w, o;

	scanf("%d%d", &n, &m);
	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(i, j, w), append(j, i, w);
	}
	scanf("%d", &k);
	memset(dd, 0x3f, n * sizeof *dd);
	while (k--) {
		scanf("%d", &i), i--;
		dd[i] = 0, pq_add_last(i);
	}
	for (h = 0; h < n; h++) {
		ii[h] = i = pq_remove_first();
		for (o = eo[i]; o--; ) {
			int d;

			j = ej[i][o], w = ew[i][o], d = dd[i] + w;
			if (dd[j] > d) {
				if (dd[j] == INF)
					pq_add_last(j);
				dd[j] = d, pq_up(j);
			}
		}
	}
	memset(ds, -1, n * sizeof *ds), memset(ww, -1, n * sizeof *ww);
	for (h = n - 1; h >= 0; h--) {
		i = ii[h];
		active[i] = 1;
		for (o = eo[i]; o--; ) {
			j = ej[i][o];
			if (active[j])
				join(i, j, dd[i]);
		}
	}
	scanf("%d", &q);
	while (q--) {
		scanf("%d%d", &i, &j), i--, j--;
		printf("%d\n", query(i, j));
	}
	return 0;
}

Compilation message (stderr)

plan.c: In function 'append':
plan.c:13:23: warning: suggest parentheses around '-' in operand of '&' [-Wparentheses]
   13 |  if (o >= 2 && (o & o - 1) == 0) {
      |                     ~~^~~
plan.c: In function 'main':
plan.c:93:2: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
   93 |  scanf("%d%d", &n, &m);
      |  ^~~~~~~~~~~~~~~~~~~~~
plan.c:99:3: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
   99 |   scanf("%d%d%d", &i, &j, &w), i--, j--;
      |   ^~~~~~~~~~~~~~~~~~~~~~~~~~~
plan.c:102:2: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
  102 |  scanf("%d", &k);
      |  ^~~~~~~~~~~~~~~
plan.c:105:3: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
  105 |   scanf("%d", &i), i--;
      |   ^~~~~~~~~~~~~~~
plan.c:131:2: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
  131 |  scanf("%d", &q);
      |  ^~~~~~~~~~~~~~~
plan.c:133:3: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
  133 |   scanf("%d%d", &i, &j), i--, j--;
      |   ^~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 10 / 10
• Subtask 2: 13 / 13
• Subtask 3: 12 / 12
• Subtask 4: 19 / 19
• Subtask 5: 46 / 46