hdu 5303 Delicious Apples（贪心）

题目链接：hdu 5303 Delicious Apples

最多转一圈，所以考虑一下转一圈的情况，和直接取完回去的情况。

#include <cstdio>
#include <cstring>
#include <vector>
#include <algorithm>

using namespace std;
typedef long long ll;
const int maxn = 1e5 + 5;

int L, N, K;
ll disl[maxn], disr[maxn];
vector<int> l, r;

ll solve () {
sort(l.begin(), l.end());
sort(r.begin(), r.end());
int sil = l.size(), sir = r.size();
for (int i = 0; i < sil; i++)
disl[i + 1] = (i + 1 <= K ? l[i] : disl[i + 1 - K] + l[i]);
for (int i = 0; i < sir; i++)
disr[i + 1] = (i + 1 <= K ? r[i] : disr[i + 1 - K] + r[i]);
ll ans = (disl[sil] + disr[sir]) * 2;

for (int i = 0; i <= sil && i <= K; i++) {
int p = max(0, sir - (K - i));
ans = min(ans, 2 * (disl[sil - i] + disr[p]) + L);
}

return ans;
}

int main () {
int cas;
scanf("%d", &cas);
while (cas--) {
l.clear();
r.clear();
int x, a;
scanf("%d%d%d", &L, &N, &K);

for (int i = 0; i < N; i++) {
scanf("%d%d", &x, &a);
for (int j = 0; j < a; j++) {
if (2 * x <= L)
l.push_back(x);
else
r.push_back(L - x);
}
}
printf("%lld\n", solve());
}
return 0;
}