static List<object> JosephusPermutation(List<object> items, int k)
{
  List<object> solution = new List<object>();
  int index = k - 1;
  int len = items.Count;
  int count = 1;
  foreach(object i in items){
    if(index<len){
      solution.Add(items[index]);
      index  = k;
    }
    else{
      index = (index - 1) - len * count;
      count  ;
    }
  }
  return solution;
}

I tried to create a function that takes every k element in the array and get an OutOfRangeException and don't know why it's happening. Can you explain me why these piece of code behaves like these? Appreciate your help!

CodePudding user response：

This line is the reason:

index = (index - 1) - len * count;

As soon as count is > 1, you're substracting a number bigger than the list length, resulting in a negative index. Removing the * count should fix this.