Codeforces Round #813 (Div. 2) 1712C - Sort Zero Solution

  

Problem Link: https://codeforces.com/contest/1712/problem/C

Solution in C++:

///La ilaha illellahu muhammadur rasulullah

///******Bismillahir-Rahmanir-Rahim******///

///Abul Hasnat  Tonmoy

///Department of CSE,23rd batch

///Islamic University,Bangladesh

///**********ALLAH IS ALMIGHTY************///

#include <bits/stdc++.h>

using namespace std;

#define ll long long int

int main()

{

    ios_base::sync_with_stdio(0);

    cin.tie(0);

    ll  n,t,i;

    cin>>t;

    while(t--)

    {

        cin>>n;

        ll a[n];

        for(i=0; i<n; i++)cin>>a[i];

        if(is_sorted(a,a+n))

        {

            cout<<"0"<<endl;

            continue;

        }

        ll ind;

        for(i=n-1; i>0; i--)

        {

            if(a[i]<a[i-1])

            {

                ind=i;

                break;

            }

        }

        map<ll,ll>mp;

        for(i=0; i<n; i++)

        {

            if(mp.find(a[i])==mp.end())

            {

                mp[a[i]]=i;

            }

        }

        ll ans;

        ans=mp.size();

        set<ll>sv;

        for(i=n-1; i>0; i--)

        {

            if(ind>mp[a[i]])

            {

                break;

            }

            sv.insert(a[i]);

        }

        ans-=sv.size();

       cout<<ans<<endl;

    }

}