测评详情

#include<bits/stdc++.h>
using namespace std;
struct node{
	int data;
	node *next;
};
node *p,*head,*r;
int main(){
	int q;
	cin>>q;
	int s,x,y;
	head=new node;
	r=head;
	p=new node;
	p->data=1;
	p->next=NULL;
	r->next=p;
	r=p;
	for(int i=1;i<=q;i++){
		cin>>s>>x;
		switch(s){
			case 1:
				cin>>y;
				r=head;
				while(r->data!=x) r=r->next;
				if(r==NULL){
					p=new node;
					p->data=y;
					p->next=NULL;
					r->next=p;
				}
				else{
					p=new node;
					p->data=y;
					p->next=r->next;
					r->next=p;
				}
				break;
			case 2:
				r=head;
				while(r->data!=x) r=r->next;
				if(r->next==NULL)
				cout<<0<<endl;
				else
				cout<<r->next->data<<endl;
				break;
			case 3:
				r=head;
				while(r->data!=x) r=r->next;
				p=r->next;
				r->next=p->next;
				break;
		}
	}
	return 0;
}