Help me in solving CHRISCANDY problem

#include<bits/stdc++.h>
using namespace std;
int main()
{
int t;cin>>t;
while(t–){
int n;
cin>>n;
vector v;
for(int i=0 ; i<n ; i++){
int x;
cin>>x;
v.emplace_back(x);
}
int a=0,b=n-1;
int count=0;
while(a<b){

    if(v[a]>v[b]){
        count++;
        b--;
    }
    else{
        a++;
    }
   }
   cout<<count<<endl;

   
}

return 0;
} what is wrong with this approach??