Submission #550651

#	Time	Username	Problem	Language	Result	Execution time	Memory
550651		rainboy	빌딩 장식 3 (JOI15_building3)	C11	100 / 100	119 ms	11952 KiB

building3

#include <stdio.h>

#define N	1000000

int main() {
	static int aa[N];
	static char used[N + 1];
	int n, h, i, j, a;
	long long ans;

	scanf("%d", &n);
	for (i = 0; i < n - 1; i++)
		scanf("%d", &aa[i]);
	used[0] = 1;
	a = 0;
	for (i = 0; i < n - 1; i++) {
		if (!used[aa[i] - 1]) {
			if (a == 0)
				a = aa[i];
			else if (a != aa[i]) {
				printf("0\n");
				return 0;
			}
		}
		used[aa[i]] = 1;
	}
	if (a == 0) {
		ans = 1, a = 0;
		for (i = 0; i < n - 1; i++) {
			if (a + 1 == aa[i])
				a++;
			ans += a;
		}
		printf("%lld\n", ans);
		return 0;
	}
	for (j = 0; j < n - 1; j++)
		if (aa[j] == a)
			break;
	if (a == 2)
		i = -1;
	else
		for (i = 0; i < n - 1; i++)
			if (aa[i] == a - 2)
				break;
	if (i > j) {
		printf("0\n");
		return 0;
	}
	ans = 0;
	for (h = i; h < j; h++)
		if (h < 0 || aa[h] != a - 1)
			ans++;
	printf("%lld\n", ans);
	return 0;
}

Compilation message (stderr)

building3.c: In function 'main':
building3.c:11:2: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
   11 |  scanf("%d", &n);
      |  ^~~~~~~~~~~~~~~
building3.c:13:3: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
   13 |   scanf("%d", &aa[i]);
      |   ^~~~~~~~~~~~~~~~~~~

• Subtask 1: 10 / 10
• Subtask 2: 30 / 30
• Subtask 3: 60 / 60