Submission #544617

#	Time	Username	Problem	Language	Result	Execution time	Memory
544617		rainboy	Senior Postmen (BOI14_postmen)	C11	100 / 100	374 ms	68016 KiB

postmen

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

#define N	500000
#define M	500000

int ij[M]; char used[M];
int *oh[N], oo[N];

void link(int i, int h) {
	int o = oo[i]++;

	if (o >= 2 && (o & o - 1) == 0)
		oh[i] = (int *) realloc(oh[i], o * 2 * sizeof *oh[i]);
	oh[i][o] = h;
}

int qu[1 + M], cnt;

void dfs(int i) {
	while (oo[i]) {
		int h = oh[i][--oo[i]];

		if (!used[h])
			used[h] = 1, dfs(i ^ ij[h]);
	}
	qu[cnt++] = i;
}

int main() {
	static char in[N];
	int n, m, h, i, j, cnt_;

	scanf("%d%d", &n, &m);
	for (i = 0; i < n; i++)
		oh[i] = (int *) malloc(2 * sizeof *oh[i]);
	for (h = 0; h < m; h++) {
		scanf("%d%d", &i, &j), i--, j--;
		ij[h] = i ^ j;
		link(i, h), link(j, h);
	}
	dfs(0);
	cnt_ = 0;
	for (h = 0; h < cnt; h++)
		if (!in[qu[h]])
			in[qu[h]] = 1, qu[cnt_++] = qu[h];
		else {
			while (qu[cnt_ - 1] != qu[h]) {
				printf("%d ", qu[cnt_ - 1] + 1);
				in[qu[--cnt_]] = 0;
			}
			printf("%d\n", qu[h] + 1);
		}
	return 0;
}

Compilation message (stderr)

postmen.c: In function 'link':
postmen.c:13:23: warning: suggest parentheses around '-' in operand of '&' [-Wparentheses]
   13 |  if (o >= 2 && (o & o - 1) == 0)
      |                     ~~^~~
postmen.c: In function 'main':
postmen.c:34:2: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
   34 |  scanf("%d%d", &n, &m);
      |  ^~~~~~~~~~~~~~~~~~~~~
postmen.c:38:3: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
   38 |   scanf("%d%d", &i, &j), i--, j--;
      |   ^~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 38 / 38
• Subtask 2: 17 / 17
• Subtask 3: 45 / 45