Mo's Algo/Sqrt Decomposition

/*
theory from here:
https://blog.anudeep2011.com/mos-algorithm/
*/
// soluton of problem : http://lightoj.com/volume_showproblem.php?problem=1188
#include<bits/stdc++.h>
using namespace std;

#define si(n) scanf("%d",&n)
#define f first
#define s second
#define mp(a,b) make_pair(a,b)
#define MAX 100005

vector<pair<int,int> >quary,original;
int arr[MAX],cnt[MAX];
int n,t,q,block;
map<pair<int,int>,int>mm;

bool compare(pair<int,int>x, pair<int,int>y)
{
    // Different blocks, sort by block.
    if (x.f/block != y.f/block)
        return x.f/block < y.f/block;

    // Same block, sort by R value
    return x.s < y.s;
}

int main()
{
    //freopen("input.txt","r",stdin);
    int i,j,k;
    si(t);
    for(int cs=1;cs<=t;cs++){
        mm.clear();
        quary.clear();
        original.clear();
        //memset(arr,0,sizeof(arr));
        memset(cnt,0,sizeof(cnt));
        si(n);si(q);
        for(i=1;i<=n;i++)
            si(arr[i]);
        for(i=1;i<=q;i++){
            int l,r;
            si(l);si(r);
            quary.push_back(mp(l,r));
            original.push_back(mp(l,r));
        }
        block=sqrt(n);
        sort(quary.begin(),quary.end(),compare);
        int curr_l=1,curr_r=1,ans=1;
        cnt[arr[1]]++;
        for(i=0;i<quary.size();i++){
            int l=quary[i].f,r=quary[i].s;
            while(curr_l<l){
                cnt[arr[curr_l]]--;
                if(!cnt[arr[curr_l]])ans--;
                curr_l++;
            }
            while(curr_l>l){
                curr_l--;
                cnt[arr[curr_l]]++;
                if(cnt[arr[curr_l]]==1)ans++;
            }

            while(curr_r<r){
               //cout<<curr_r<<endl;
                curr_r++;
                cnt[arr[curr_r]]++;
                if(cnt[arr[curr_r]]==1)ans++;
            }
            while(curr_r>r){
                cnt[arr[curr_r]]--;
                if(!cnt[arr[curr_r]])ans--;
                curr_r--;
            }
            //cout<<l<<' '<<r<<' '<<curr_l<<' '<<curr_r<<endl;
            mm[mp(l,r)]=ans;
        }
        printf("Case %d:\n",cs);
        for(i=0;i<original.size();i++){
            printf("%d\n",mm[mp(original[i].f,original[i].s)]);
        }
    }
    return 0;
}