Submission #471171

#	Time	Username	Problem	Language	Result	Execution time	Memory
471171		rainboy	ZigZag (COCI17_zigzag)	C11	80 / 80	72 ms	5852 KiB

zigzag

#include <stdio.h>
#include <string.h>
#include <sys/time.h>

#define N	100000
#define L	21
#define A	26

unsigned int X;

void srand_() {
	struct timeval tv;

	gettimeofday(&tv, NULL);
	X = tv.tv_sec ^ tv.tv_usec | 1;
}

int rand_() {
	return (X *= 3) >> 1;
}

char ss[N][L + 1]; int ii[N];

void sort(int *ii, int l, int r) {
	while (l < r) {
		int i = l, j = l, k = r, i_ = ii[l + rand_() % (r - l)], tmp;

		while (j < k) {
			int c = strcmp(ss[ii[j]], ss[i_]);

			if (c == 0)
				j++;
			else if (c < 0) {
				tmp = ii[i], ii[i] = ii[j], ii[j] = tmp;
				i++, j++;
			} else {
				k--;
				tmp = ii[j], ii[j] = ii[k], ii[k] = tmp;
			}
		}
		sort(ii, l, i);
		l = k;
	}
}

int main() {
	static int ll[A], rr[A], kk[A];
	int n, m, i, a;

	srand_();
	scanf("%d%d", &n, &m);
	for (i = 0; i < n; i++)
		scanf("%s", ss[i]);
	for (i = 0; i < n; i++)
		ii[i] = i;
	sort(ii, 0, n);
	for (a = 0, i = 0; a < A; a++) {
		ll[a] = i;
		while (i < n && ss[ii[i]][0] == a + 'a')
			i++;
		rr[a] = i;
	}
	while (m--) {
		static char s[2];

		scanf("%s", s), a = s[0] - 'a';
		printf("%s\n", ss[ii[ll[a] + kk[a]++ % (rr[a] - ll[a])]]);
	}
	return 0;
}

Compilation message (stderr)

zigzag.c: In function 'srand_':
zigzag.c:15:16: warning: suggest parentheses around arithmetic in operand of '|' [-Wparentheses]
   15 |  X = tv.tv_sec ^ tv.tv_usec | 1;
      |      ~~~~~~~~~~^~~~~~~~~~~~
zigzag.c: In function 'main':
zigzag.c:51:2: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
   51 |  scanf("%d%d", &n, &m);
      |  ^~~~~~~~~~~~~~~~~~~~~
zigzag.c:53:3: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
   53 |   scanf("%s", ss[i]);
      |   ^~~~~~~~~~~~~~~~~~
zigzag.c:66:3: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
   66 |   scanf("%s", s), a = s[0] - 'a';
      |   ^~~~~~~~~~~~~~

• Subtask 1: 80 / 80