gistfile1.groovy

  
  static int binarySearch(int[] values, int val) throws Exception
  {
    return binarySearchHelp(values, val, 0, values.length - 1);
  }

  static int binarySearchHelp(int[] values, int val, int start, int end)
      throws Exception
  {
    if (start > end)
      throw new Exception("Somehow indexes have gotten reversed");
    if (start == end)
      return values[start]==val ? start : -1;
    int mid = (start + end) / 2;
    if (values[mid] > val)
      return binarySearchHelp(values, val, start, mid);
    else if (values[mid] < val)
      return binarySearchHelp(values, val, mid + 1, end);
    else
      return values[mid]==val ? mid : -1; 
  }