题目：P7870

#include<iostream>
#include<cstdio>
#include<cstring>
#include<string>
#include<algorithm>
#include<cmath>
#include<cstdlib>
#include<iomanip>
#include<queue>
#include<list>
#include<math.h>
#include<cctype>
#include<map>
#include<stack>
#define maxn 1000010
using namespace std;
typedef long long ll;
typedef unsigned long wf;
typedef unsigned int u32;
typedef unsigned long long u64;
ll n,k,l,r,a[maxn],head=1,ans=0;
int main(){
	ios::sync_with_stdio(0);
	cin>>n;
	while(n--){
		cin>>k;
		if(k==1){
			cin>>l>>r;
			for(ll i=l;i<=r;i++) a[head++]=i;
		}
		else{
			cin>>l;
			ans=0;
			for(ll i=head;i>=head-l;i--){
				if(i>0){
				ans+=a[i];
				a[i]=0;
				}
			}
			head-=l;
			cout<<ans<<"\n";
		}
	}
    return 0;
}

感谢