多校第二场C题

水贪心

#include<algorithm>
#include<iostream>
#include<cstring>
#include<cstdlib>
#include<cstdio>
#include<queue>
#include<set>
using namespace std;
typedef long long ll;
typedef pair<int,int> pii;
#define MAXN 500005
#define mod (ll)(1e9+7)
int a[MAXN];
multiset<int> b;
int main(){
	int n;
	priority_queue<pii> que;
	while(~scanf("%d",&n)){
		while(!que.empty())
			que.pop();
		for(int i=1;i<=n;i++){
			scanf("%d",&a[i]);
			que.push(make_pair(a[i]-i,i));
		}
		for(int i=1;i<=n;i++){
			int x;
			scanf("%d",&x);
			b.insert(x);
		}
		ll ans=0;
		set<int>::iterator it;
		for(int i=1;i<=n;i++){
			pii x;
			do{
				x=que.top();	que.pop();
				it=b.upper_bound(x.second);
			}while(it==b.begin());
			it--;
			que.push(x);//cout<<pos<<endl;
			ans=(ans+x.first)%mod;
			b.erase(it);
			que.push(make_pair(x.first-i-n,n+i));
			//cout<<ans<<endl;
		}
		cout<<ans<<endl;
	}
	return 0;
}