Accepted C++ Code:

    ios_base::sync_with_stdio(false);
cin.tie(NULL);
    int q;
cin >> q;
vector<int> ans;
unordered_map<int, int> umap;
unordered_map<int, int> query;
while(q--){
    int a,b,temp;
    cin >> a >> b;
    switch (a){
        case 1:
            temp=umap[b];
            if(query[temp]>0)
                query[temp]--;
            umap[b]++;
            query[temp+1]++;
            break;
        case 2:
            temp=umap[b];
            if(temp>0){
                query[temp]--;
                umap[b]--;
                query[temp-1]++;
            }
            break;
        case 3:
            if(query[b]>0){
                ans.push_back(1);
            }else{
                ans.push_back(0);
            }
            break;
    }
}
for(int i=0;i<ans.size();i++){
    cout << ans[i] << "\n";
}