Submission #440011

#	Time	Username	Problem	Language	Result	Execution time	Memory
440011		dongliu0426	Feast (NOI19_feast)	C++14	12 / 100	506 ms	20292 KiB

feast

#include <bits/stdc++.h>
using namespace std;

#define N	300000
#define INF	0x3f3f3f3f3f3f3f3f

int n, k, a[N + 1];
pair<long double, int> dp[N + 1][2];

int main() {
	scanf("%d%d", &n, &k);
	long long sum = 0;
	for (int i = 1; i <= n; ++i)
		scanf("%d", a + i), sum += a[i];
	auto check = [&](long double penalty) {
		dp[0][0] = {0, 0}, dp[0][1] = {-INF, 0};
		for (int i = 1; i <= n; ++i) {
			dp[i][0] = max(dp[i - 1][0], dp[i - 1][1]);
			dp[i][1] = max(make_pair(dp[i - 1][1].first + a[i], dp[i - 1][1].second),
				make_pair(dp[i - 1][0].first + a[i] - penalty, dp[i - 1][0].second + 1));
		}
		return max(dp[n][0], dp[n][1]).second >= k;
	};
	long double lower = 0, upper = sum;
	for (int it = 0; it < 100; ++it) {
		long double mid = (lower + upper) / 2;
		if (check(mid)) {
			lower = mid;
		} else {
			upper = mid;
		}
	}
	long double penalty = lower;
	check(penalty);
	printf("%lld\n", (long long) round(penalty * k + max(dp[n][0], dp[n][1]).first));
}

Compilation message (stderr)

feast.cpp: In function 'int main()':
feast.cpp:11:7: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   11 |  scanf("%d%d", &n, &k);
      |  ~~~~~^~~~~~~~~~~~~~~~
feast.cpp:14:8: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   14 |   scanf("%d", a + i), sum += a[i];
      |   ~~~~~^~~~~~~~~~~~~

• Subtask 1: 4 / 4
• Subtask 2: 8 / 8
• Subtask 3: 0 / 18
• Subtask 4: 0 / 10
• Subtask 5: 0 / 11
• Subtask 6: 0 / 20
• Subtask 7: 0 / 29