luogu P4694 [PA2013]Raper

https://www.luogu.com.cn/problem/P4694

首先可以用\(wqs\)二分去掉\(K\)的那个限制
然后可以发现剩下的就是一个模拟费用流了

code:

#include<bits/stdc++.h>
#define ll long long
#define N 500050
using namespace std;
int n, k, a[N], b[N];
ll ans;
int check(ll mid) {
    priority_queue<pair<ll, int> > q;
    ans = 0;
    int ret = 0;
    for(int i = 1; i <= n; i ++) {
        q.push(make_pair(- a[i], 0));
        int x = -q.top().first, y = q.top().second;
        if(x + b[i] + mid <= 0) {
            ans += x + b[i] + mid;
            if(!y) ret ++;
            q.pop(); q.push(make_pair(b[i] + mid, -1));
        }
    }
    return ret >= k;
}
int main() {
    scanf("%d%d", &n, &k);
    for(int i = 1; i <= n; i ++) scanf("%d", &a[i]);
    for(int i = 1; i <= n; i ++) scanf("%d", &b[i]);
    ll l = -1e12, r = 1e12;
    while(l + 1 < r) {
        ll mid = (l + r) >> 1;
        if(check(mid)) l = mid;
        else r = mid;
    }
    check(l);
    printf("%lld", ans - l * k);
    return 0;
}