Submission #824137

#	Time	Username	Problem	Language	Result	Execution time	Memory
824137		rainboy	Flip it and Stick it (CCO23_day2problem1)	C11	18 / 25	3 ms	664 KiB

Main

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

#define N	200000

int max(int a, int b) { return a > b ? a : b; }

int count(char *aa, int n, char *bb, int m) {
	int i, k;

	k = 0;
	for (i = 0; i + m <= n; i++)
		if (strncmp(aa + i, bb, m * sizeof *bb) == 0)
			k++;
	return k;
}

int main() {
	static char aa[N + 1], bb[4];
	int n, m, i, j, a, d, k1, k2, k, l;

	scanf("%s%s", aa, bb), n = strlen(aa), m = strlen(bb);
	k = count(aa, n, bb, m);
	if (m == 1)
		printf(k != 0 ? "-1\n" : "0\n");
	else if (m == 2) {
		if (bb[0] != bb[1])
			printf("%d\n", k);
		else {
			d = 0;
			for (i = 0; i < n; i++)
				d += aa[i] == bb[0] ? 1 : -1;
			printf("%d\n", d > 1 ? -1 : k);
		}
	} else {
		if (bb[0] != bb[2])
			printf("%d\n", k);
		else if (bb[0] != bb[1])
			printf("%d\n", (k + 1) / 2);
		else {
			k1 = k2 = 0, k = 0, l = 0;
			for (i = -1, j = 0; j <= n; j++)
				if (j == n || aa[j] != bb[0]) {
					a = j - i - 1;
					if (a == 1)
						k1++;
					else if (a == 0)
						k2++;
					else {
						a -= 2;
						k += a, l += (a + 1) / 2;
					}
					i = j;
				}
			printf("%d\n", k >= k1 + k2 * 2 ? -1 : max(k - k2, l));
		}
	}
	return 0;
}

Compilation message (stderr)

Main.c: In function 'main':
Main.c:22:2: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
   22 |  scanf("%s%s", aa, bb), n = strlen(aa), m = strlen(bb);
      |  ^~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 1 / 1
• Subtask 2: 3 / 3
• Subtask 3: 4 / 4
• Subtask 4: 5 / 5
• Subtask 5: 5 / 5
• Subtask 6: 0 / 7