package demo;
import java.util.Scanner;
public class Main {
private static int maxLen(int arr[],int m,int n){
if(m>=n) return 100;//补交卡的数量大于缺交天数的数量的话,连续的天数肯定是100天,因为如果你只缺了一天然后补交卡大于一的话,连续的天数肯定是100
int res = arr[m]-1;//拿到的数据是第二个
for(int i=0;i+m+1<n;i++){
res = Math.max(res, arr[i+m+1]-arr[i]-1);
}
res = Math.max(res, 100-arr[n-m-1]);
return res;
}
public static void main(String args[]){
Scanner sc = new Scanner(System.in);
/* Scanner sc = null;
try {
sc = new Scanner(new FileInputStream("C:\\Users\\ddguo\\Desktop\\input.txt"));
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}*/
int num = sc.nextInt();
while(num-->0){
int n = sc.nextInt();//缺交天数的数量
int m = sc.nextInt();//补交卡数量
int arr[] = new int[n];
for(int i=0;i<n;i++){
arr[i]= sc.nextInt();
}
System.out.println(maxLen(arr, m, n));
}
sc.close();
}
}