Submission #544722

#	Time	Username	Problem	Language	Result	Execution time	Memory
544722		rainboy	Hacker (BOI15_hac)	C11	100 / 100	75 ms	7224 KiB

hac

#include <stdio.h>

#define N	500000

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

int main() {
	static int aa[N], ss[N], qu[N * 2];
	int n, k, i, head, cnt, ans;

	scanf("%d", &n), k = (n + 1) / 2;
	for (i = 0; i < n; i++) {
		scanf("%d", &aa[i]);
		if (i * 2 < n)
			ss[0] += aa[i];
	}
	for (i = 1; i < n; i++)
		ss[i] = ss[i - 1] - aa[i - 1] + aa[(i + k - 1) % n];
	head = cnt = 0, ans = 0;
	for (i = 0; i < n + k; i++) {
		while (cnt && ss[qu[head + cnt - 1] % n] >= ss[i % n])
			cnt--;
		qu[head + cnt++] = i;
		if (i >= k - 1) {
			ans = max(ans, ss[qu[head] % n]);
			if (qu[head] == i - k + 1)
				head++, cnt--;
		}
	}
	printf("%d\n", ans);
	return 0;
}

Compilation message (stderr)

hac.c: In function 'main':
hac.c:11:2: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
   11 |  scanf("%d", &n), k = (n + 1) / 2;
      |  ^~~~~~~~~~~~~~~
hac.c:13:3: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
   13 |   scanf("%d", &aa[i]);
      |   ^~~~~~~~~~~~~~~~~~~

• Subtask 1: 20 / 20
• Subtask 2: 20 / 20
• Subtask 3: 20 / 20
• Subtask 4: 40 / 40