Hello there

I'm trying to slove this problem using segment tree

i'm trying to process the queries offline and doing data compression on the given numbers

but i keep getting WA and I've been trying to look for the reason for a couple of days with no use

if someone could find where i am mistaken that would be great :D

here is my code

#include <bits/stdc++.h>
using namespace std;

const long long mod = 1e9 + 7;
const double eps = 1e-9;
const double PI = atan(1.0);
#define readFile freopen("input","r",stdin);
#define writeFile freopen("output","w",stdout);
#define fastIO ios::sync_with_stdio(0);
typedef pair<int,int> ii;
typedef long long ll;
const int N = 200005;
int n;
map<int,int> chash;
int rev[N];
vector<pair<char,int> > query;
vector<int> inserts;
int tree[2<<19];
int cnt=0;

void insert(int node,int l,int r,int idx){
    if (l==r) {
        if (!tree[node]) cnt++;
        tree[node] = 1;
        return;
    }
    int mid = (l+r)>>1;
    if (idx>mid) insert(node<<1|1,mid+1,r,idx);
    else insert(node<<1,l,mid,idx);
    tree[node] = tree[node<<1]+tree[node<<1|1];
}

void deleter(int node,int l,int r,int idx){
    if (l==r){
        if (tree[node]) cnt--;
        tree[node] = 0;
        return;
    }
    int mid = (l+r)>>1;
    if (idx<=mid)
        deleter(node<<1,l,mid,idx);
    else 
        deleter(node<<1|1,mid+1,r,idx);
    tree[node] = tree[node<<1]+tree[node<<1|1];
}

int getk(int node,int l,int r,int k){
    if (l==r) return rev[l];
    int mid = (l+r)>>1;
    if (k<=tree[node<<1]) 
        return getk(node<<1,l,mid,k);
    return getk(node<<1|1,mid+1,r,k-tree[node<<1]);
}

int queryk(int node,int l,int r,int x){
    if (l==r) return 0;
    int mid=(l+r)>>1;
    if (x<=mid) return queryk(node<<1,l,mid,x);
    return tree[node<<1]+queryk(node<<1|1,mid+1,r,x);
}


int main(){
#ifndef ONLINE_JUDGE
    readFile;
#endif
    fastIO;
    cin>>n;
    for(int i=0;i<n;i++){
        char c; int num; cin>>c>>num;
        query.push_back(make_pair(c,num));
        inserts.push_back(num);
    }
    sort(inserts.begin(),inserts.end());
    int pointer=1;
    chash[inserts[0]] = pointer;
    rev[pointer++] = inserts[0];
    for(int i=1;i<inserts.size();i++){
        if (inserts[i]!=inserts[i-1]){
            chash[inserts[i]] = pointer;
            rev[pointer++] = inserts[i];
        }
    }
    memset(tree,0,sizeof(tree));
    for(int i=0;i<query.size();i++){
        if (query[i].first=='I') {
            insert(1,1,n,chash[query[i].second]);
            continue;
        }
        if (query[i].first=='D') {
            deleter(1,1,n,chash[query[i].second]);
            continue;
        }
        if (query[i].first=='K') {
            if (query[i].second>cnt) cout<<"INVALID\n";
            else cout<<getk(1,1,n,min(N,query[i].second))<<"\n";
            continue;
        }
        if (query[i].first=='C') {
            cout<<queryk(1,1,n,chash[query[i].second])<<"\n";
        }
    }
}