Submission #545918

#	Time	Username	Problem	Language	Result	Execution time	Memory
545918		rainboy	Global Warming (CEOI18_glo)	C11	100 / 100	162 ms	8400 KiB

glo

#include <stdio.h>

#define N	200000

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

unsigned int X = 12345;

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

int aa[N * 2];

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)
			if (aa[ii[j]] == aa[i_])
				j++;
			else if (aa[ii[j]] < aa[i_]) {
				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;
	}
}

void update(int *ft, int i, int n, int x) {
	while (i < n) {
		ft[i] = max(ft[i], x);
		i |= i + 1;
	}
}

int query(int *ft, int i) {
	int x = 0;

	while (i >= 0) {
		x = max(x, ft[i]);
		i &= i + 1, i--;
	}
	return x;
}

int main() {
	static int ii[N * 2], ft1[N * 2], ft2[N * 2], dp[N], dq[N];
	int n, x, i, a;

	scanf("%d%d", &n, &x);
	for (i = 0; i < n; i++)
		scanf("%d", &aa[i]), aa[n + i] = aa[i] + x;
	for (i = 0; i < n * 2; i++)
		ii[i] = i;
	sort(ii, 0, n * 2);
	for (i = 0, a = 0; i < n * 2; i++)
		aa[ii[i]] = i + 1 == n * 2 || aa[ii[i + 1]] != aa[ii[i]] ? a++ : a;
	for (i = 0; i < n; i++) {
		dp[i] = query(ft1, aa[i] - 1) + 1;
		dq[i] = query(ft2, aa[n + i] - 1) + 1;
		update(ft1, aa[i], n * 2, dp[i]), update(ft2, aa[i], n * 2, dp[i]);
		update(ft2, aa[n + i], n * 2, dq[i]);
	}
	printf("%d\n", max(query(ft1, n * 2 - 1), query(ft2, n * 2 - 1)));
	return 0;
}

Compilation message (stderr)

glo.c: In function 'main':
glo.c:55:2: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
   55 |  scanf("%d%d", &n, &x);
      |  ^~~~~~~~~~~~~~~~~~~~~
glo.c:57:3: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
   57 |   scanf("%d", &aa[i]), aa[n + i] = aa[i] + x;
      |   ^~~~~~~~~~~~~~~~~~~

• Subtask 1: 5 / 5
• Subtask 2: 10 / 10
• Subtask 3: 13 / 13
• Subtask 4: 10 / 10
• Subtask 5: 20 / 20
• Subtask 6: 17 / 17
• Subtask 7: 25 / 25