#include <bits/stdc++.h>
using namespace std;
int main(){
int t; cin>>t;
while(t--){
int n,k; cin>>n>>k;
vector<int> v;
for (int i = 0; i < n; i++){
int m;cin>>m;v.push_back(m);
}
int store=-1;
int check=0;
for (int i = 0; i < k; i++){
for(int j=0;j+1<n;j++){
if(v[j]<v[j+1]){
check=0;
store=j+1;
v[j]++;
break;
}
check=1;
store=-1;
}
if(check) break;
}
cout<<store<<endl;
}
}
1692B - All Distinct | 1156C - Match Points |
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1672C - Unequal Array | 1706C - Qpwoeirut And The City |
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1401C - Mere Array | 1613B - Absent Remainder |
1536B - Prinzessin der Verurteilung | 1699B - Almost Ternary Matrix |
1545A - AquaMoon and Strange Sort | 538B - Quasi Binary |
424A - Squats | 1703A - YES or YES |