代码：

#include <iostream>
#include <cstring>

using namespace std;

const int N = 100003;

int h[N], e[N], ne[N], idx;

void insert(int x)
{
    int k = (x % N + N) % N;//哈希,保证取模后为正数
    e[idx] = x;
    ne[idx] = h[k];
    h[k] = idx++;
}

bool find(int x)
{
    int k = (x % N + N) % N;
    for(int i = h[k]; i != -1; i = ne[i])
        if(e[i] == x)
            return true;

    return false;
}

int main()
{
    int n;
    scanf("%d", &n);
    
    memset(h, -1, sizeof h);
    
    while(n--)
    {
         char op[2];
         int x;
         scanf("%s%d", op, &x);
         
          if(*op == 'I') insert(x);
          else
          {
              if(find(x))puts("Yes");
              else puts("No");          
          }                       
    }
    return 0;
}

代码：

#include <iostream>
#include <cstring>

using namespace std;

const int N = 200003, null = 0x3f3f3f3f;

int h[N];

int find(int x)
{
    int k = (x % N + N) % N;
    while(h[k] != null && h[k] != x)
    {
        k++;
        if(k == N) k = 0;    
    }
    
    return k;
}

int main()
{
    int n;
    scanf("%d", &n);
    
    memset(h, 0x3f, sizeof h);
    
    while(n--)
    {
        char op[2];
        int x;
        scanf("%s%d", op, &x);
        
        int k = find(x);
        if(*op == 'I') h[k] = x;
        else
        {
            if(h[k] != null) puts("Yes");
            else puts("No");        
        }                
    }
    
    return 0;
}