Submission #590205

#	Time	Username	Problem	Language	Result	Execution time	Memory
590205		rainboy	Uplifting Excursion (BOI22_vault)	C11	80 / 100	297 ms	4424 KiB

vault

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

#define N	100
#define INF	0x3f3f3f3f

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

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

	if (a > 0) {
		for (s = 0; s <= s_; 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 <= s_; 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 <= s_; s++)
			dq[s] = dp[s] == -INF ? -INF : dp[s] + s / a * c;
		for (r = 0; r < a; r++) {
			head = cnt = 0;
			for (s = (s_ - 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 <= s_; s++)
			if (dp[s] != -INF)
				dp[s] += k * c;
	}
}

long long solve(long long *kk, int n, long long s_) {
	static int dp[N * N * 2 + 1], dq[N + 1][N * N + 1];
	int a, r1, r2;
	long long s, s0, s1, s2, lower, upper, k0, ans;

	for (s = 0; s <= n * n; s++)
		dp[s] = -INF;
	dp[0] = 0;
	for (a = n; a >= 0; a--) {
		memcpy(dq[a], dp, (n * n + 1) * sizeof *dp);
		update(dp, n * n, a, min(kk[n + a], n), 1);
	}
	for (s = 0; s <= n * n * 2; s++)
		dp[s] = -INF;
	dp[n * n + 0] = 0;
	s0 = 0, k0 = 0;
	for (a = -n; a < 0; a++) {
		update(dp, n * n * 2, a, min(kk[n + a], n), -1);
		s0 += kk[n + a] * a, k0 += kk[n + a];
	}
	ans = -INF;
	for (a = 0; a <= n; a++) {
		if (a == 0) {
			for (s1 = 0; s1 <= n * n * 2; s1++) {
				s2 = s_ - s0 + s1 - n * n;
				if (dp[s1] != -INF && s2 >= 0 && s2 <= n * n && dq[a][s2] != -INF)
					ans = max(ans, k0 + dp[s1] + dq[a][s2] + kk[n + a]);
			}
		} else
			for (r1 = 0; r1 < a; r1++) {
				r2 = ((s_ - s0 - n * n + r1) % a + a) % a;
				for (s1 = r1, lower = r2, upper = r2; s1 <= n * n * 2; s1 += a)
					if (dp[s1] != -INF) {
						while (lower <= n * n && s0 - s1 + n * n + lower < s_ - kk[n + a] * a)
							lower += a;
						while (upper <= n * n && s0 - s1 + n * n + upper <= s_)
							upper += a;
						for (s2 = lower; s2 < upper; s2 += a)
							if (dq[a][s2] != -INF)
								ans = max(ans, k0 + dp[s1] + dq[a][s2] + (s_ - s0 + s1 - s2 - n * n) / a);
					}
			}
		update(dp, n * n * 2, a, min(kk[n + a], n), -1);
		s0 += kk[n + a] * a, k0 += kk[n + a];
	}
	return ans;
}

int main() {
	static long long kk[N * 2 + 1];
	int n, a, r;
	long long s, ans, tmp;

	scanf("%d%lld", &n, &s);
	if (n > N)
		return 0;
	for (a = -n; a <= n; a++)
		scanf("%lld", &kk[n + a]);
	ans = -INF;
	for (r = 0; r < 2; r++) {
		ans = max(ans, solve(kk, n, s));
		for (a = 1; a <= n; a++)
			tmp = kk[n - a], kk[n - a] = kk[n + a], kk[n + a] = tmp;
		s = -s;
	}
	if (ans == -INF)
		printf("impossible\n");
	else
		printf("%lld\n", ans);
	return 0;
}

Compilation message (stderr)

vault.c: In function 'main':
vault.c:109:2: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
  109 |  scanf("%d%lld", &n, &s);
      |  ^~~~~~~~~~~~~~~~~~~~~~~
vault.c:113:3: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
  113 |   scanf("%lld", &kk[n + a]);
      |   ^~~~~~~~~~~~~~~~~~~~~~~~~

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