Submission #590967

#	Time	Username	Problem	Language	Result	Execution time	Memory
590967		rainboy	Uplifting Excursion (BOI22_vault)	C11	0 / 100	11 ms	360 KiB

vault

/* https://www.boi2022.de/wp-content/uploads/2022/05/boi2022-day1-vault-spoiler.pdf */
#include <stdio.h>
#include <string.h>

#define N	300
#define M	(N * (N + 1))
#define INF	0x3f3f3f3f

long long min(long long a, long long b) { return a < b ? a : b; }

void update(int *dp, int m, int a, int k, int c) {
	static int dq[M * 2 + 1], qu[M * 2 + 1];
	int s, r, head, cnt;

	if (a > 0) {
		for (s = 0; s <= m; s++)
			dq[s] = dp[s] == -INF ? -INF : dp[s] - s / a * c;
		for (r = 0; r < a; r++) {
			head = cnt = 0;
			for (s = r; s <= m; s += a) {
				if (dq[s] != -INF) {
					while (cnt && dq[qu[head + cnt - 1]] < dq[s])
						cnt--;
					qu[head + cnt++] = s;
				}
				dp[s] = cnt == 0 ? -INF : dq[qu[head]] + s / a * c;
				if (cnt && qu[head] == s - a * k)
					head++, cnt--;
			}
		}
	} else if (a < 0) {
		a = -a;
		for (s = 0; s <= m; s++)
			dq[s] = dp[s] == -INF ? -INF : dp[s] + s / a * c;
		for (r = 0; r < a; r++) {
			head = cnt = 0;
			for (s = (m - r) / a * a + r; s >= 0; s -= a) {
				if (dq[s] != -INF) {
					while (cnt && dq[qu[head + cnt - 1]] < dq[s])
						cnt--;
					qu[head + cnt++] = s;
				}
				dp[s] = cnt == 0 ? -INF : dq[qu[head]] - s / a * c;
				if (cnt && qu[head] == s + a * k)
					head++, cnt--;
			}
		}
	} else {
		if (c <= 0)
			return;
		for (s = 0; s <= m; s++)
			if (dp[s] != -INF)
				dp[s] += k * c;
	}
}

int main() {
	static long long kk[N * 2 + 1], ll[N * 2 + 1];
	static int dp[M * 2 + 1];
	int n, m, a, s;
	long long sum_, sum, l, ans;

	scanf("%d%lld", &n, &sum_), m = n * (n + 1);
	sum = 0;
	for (a = -n; a <= n; a++) {
		scanf("%lld", &kk[n + a]);
		ll[n + a] = kk[n + a], sum += ll[n + a] * a;
	}
	if (sum > sum_) {
		for (a = n; a > 0 && sum > sum_; a--) {
			l = min(ll[n + a], (sum - sum_ + a - 1) / a);
			ll[n + a] -= l, sum -= l * a;
		}
		if (sum > sum_) {
			printf("impossible\n");
			return 0;
		}
	} else {
		for (a = n; a > 0 && sum < sum_; a--) {
			l = min(ll[n - a], (sum_ - sum + a - 1) / a);
			ll[n - a] -= l, sum += l * a;
		}
		if (sum < sum_) {
			printf("impossible\n");
			return 0;
		}
	}
	for (s = 0; s <= m * 2; s++)
		dp[s] = -INF;
	dp[m + 0] = 0;
	for (a = -n; a <= n; a++) {
		update(dp, m * 2, a, min(ll[n + a], n + 1), -1);
		update(dp, m * 2, a, min(kk[n + a] - ll[n + a], n + 1), 1);
	}
	if (dp[m + sum_ - sum] == -INF) {
		printf("impossible\n");
		return 0;
	}
	ans = dp[m + sum_ - sum];
	for (a = -n; a <= n; a++)
		ans += ll[n + a];
	printf("%lld\n", ans);
	return 0;
}

Compilation message (stderr)

vault.c: In function 'main':
vault.c:63:2: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
   63 |  scanf("%d%lld", &n, &sum_), m = n * (n + 1);
      |  ^~~~~~~~~~~~~~~~~~~~~~~~~~
vault.c:66:3: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
   66 |   scanf("%lld", &kk[n + a]);
      |   ^~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 0 / 5
• Subtask 2: 0 / 15
• Subtask 3-1: 0 / 10
• Subtask 3-2: 0 / 10
• Subtask 4-1: 0 / 10
• Subtask 4-2: 0 / 10
• Subtask 5-1: 0 / 10
• Subtask 5-2: 0 / 10
• Subtask 6-1: 0 / 10
• Subtask 6-2: 0 / 10