1.拉链法

#include<iostream>
#include<cstring>
using namespace std;
const int N=1e5+3;
int h[N],v[N],ne[N],idx;
void insert(int x)
{
    int k=(x%N+N)%N;
    v[idx]=x;
    ne[idx]=h[k];
    h[k]=idx++;
}
bool find(int x)
{
    int k=(x%N+N)%N;
    int i=h[k];
    while(i!=-1 && v[i]!=x) i=ne[i];
    if(v[i]==x) return true;
    return false;
}
int main()
{
   int n;
   memset(h,-1,sizeof h);
   cin>>n;
   while(n--)
   {
       char op;
       int x;
       cin>>op;
       cin>>x;
       if(op=='I') insert(x);
       else
       {
           if(find(x)) cout<<"Yes"<<endl;
           else cout<<"No"<<endl;
       }
   }
   return 0;
}

2.开放寻址法

#include<iostream>
#include<cstring>
using namespace std;
const int N=2e5+3;
int h[N],flag=0x3f3f3f3f;
int find(int x)
{
    int k=(x%N+N)%N;
    while(h[k]!=flag && h[k]!=x)
    {
        k++;
        if(k==N) k=1;
    }
    return k;
}
int main()
{
   int n;
   memset(h,0x3f,sizeof h);
   cin>>n;
   while(n--)
   {
       char op;
       int x;
       cin>>op;
       cin>>x;
       if(op=='I') h[find(x)]=x;
       else
       {
           if(h[find(x)]==x) cout<<"Yes"<<endl;
           else cout<<"No"<<endl;
       }
   }
   return 0;
}