一维vector
abs绝对值因为会有负数

C++ 代码

#include<iostream>
#include<vector>
#include<algorithm>
#include<cmath>
using namespace std;
vector<int> a[100010];
int main(){
    int n;
    cin>>n;
    char f;
    int num;
    bool flag = 0;
    while(n--){
        cin>>f;
        if(f == 'I'){
            cin>>num;
            a[abs(num % 100000)].push_back(num);
        }
        else{
            flag = 0;
            cin>>num;
            for(int i = 0;i < a[abs(num % 100000)].size();i++){
                if(a[abs(num % 100000)][i] == num){
                    cout<<"Yes"<<endl;
                    flag = 1;
                    break;
                }
            }
            if(!flag) cout << "No" << endl;
        }
    }
}