(CF1394 A)Boboniu Chats with Du

开始本来以为可以直接贪心的。。。最后还是得dp统计答案

①把大于m和小于等于m的分成2组降序求前缀和,小于等于m的size为cnt,大于的为tot

②将i从0枚举到cnt,指选择i个小于等于m的数(从大到小贪心),剩下n-i个数,再从其中选择(n-i+d)/(d+1)个禁言单元(每一次禁言消耗d+1天,但最后一个单元的禁言时间可以超过n,因此需要上取整)

\(ans=max(ans,a[i] + (bigsiz > tot ? b[tot] : b[bigsiz]))\);

#include<bits/stdc++.h>
using namespace std;
#define ll long long
#define fastio ios::sync_with_stdio(false),cin.tie(NULL),cout.tie(NULL)
const int maxn = 1e5 + 10;
const int inf = 1e8;
ll mod = 1e9 + 7;

int cnt, tot;

void pre(vector<ll> &a,int n)
{
    sort(a.begin() + 1, a.end(), greater<>());
    for (int i = 1; i <= n; i++)
        a[i] += a[i - 1];
}

int main()
{
    //freopen("C:\\1.in", "r", stdin);
    fastio;
    ll n, m, d;
    cin >> n >> d >> m;
    vector<ll>a(n + 1), b(n + 1);
    for (int i = 1; i <= n; i++)
    {
        ll x;
        cin >> x;
        if (x <= m)a[++cnt] = x;
        else b[++tot] = x;
    }
    pre(a, cnt);
    pre(b, tot);
    ll ans = 0;
    for (int i = 0; i <= cnt; i++)
    {
        int bigsiz = (n - i + d) / (d + 1);//剩下的除d+1上取整
        ans = max(ans, a[i] + (bigsiz > tot ? b[tot] : b[bigsiz]));
    }
    cout << ans;

    return 0;

}
原文地址:https://www.cnblogs.com/ruanbaiQAQ/p/13500884.html