P5076 RE 求调，0pts

#include<bits/stdc++.h>
using namespace std;
struct node{
	node *nxt;
	node *pre;
	int val;
};
node *head;
int q,o,x;
int main(){
	cin>>q;
	while(q--){
		cin>>o>>x;
		if(o==1){
			int cnt=0;
			node *p;
			p=head;
			while(p=p->nxt){
				cnt++;
				if(p->val==x){
					cout<<cnt<<"\n";
					break;
				}
			}
		}else if(o==2){
			int cnt=0;
			node *p;
			p=head;
			while(p=p->nxt){
				cnt++;
				if(cnt==x){
					cout<<p->val<<"\n";
					break;
				}
			}
		}else if(o==3){
			bool f=0;
			node *p;
			p=head;
			while(p=p->nxt){
				if(p->nxt->val==x){
					cout<<p->val<<"\n";
					f=1;
					break;
				}
			}
			if(f==0)cout<<"-2147483647\n";
		}else if(o==4){
			bool f=0;
			node *p;
			p=head;
			while(p=p->nxt){
				if(p->val==x){
					cout<<p->nxt->val<<"\n";
					f=1;
					break;
				}
			}
			if(f==0)cout<<"2147483647\n";
		}else{
			node *p;
			p=head;
			while(p=p->nxt){
				if(p->val<=x&&p->nxt->val>=x){
					node *ix=new node;
					ix->nxt=p->nxt;
					p->nxt=ix;
				}
			}
		}
	}
}