input: Write a python function to search for a target value in a sorted list using binary search.
  assert searchSortedList([1, 2, 3, 4, 5, 6, 7, 8, 9], 5) == 4
  assert searchSortedList([10, 20, 30, 40, 50], 25) == -1
  assert searchSortedList([2, 4, 6, 8, 10], 6) == 2
output: def searchSortedList(arr, target):
      left, right = 0, len(arr) - 1
      while left <= right:
          mid = (left + right) // 2
          if arr[mid] == target:
              return mid
          elif arr[mid] < target:
              left = mid + 1
          else:
              right = mid - 1
      return -1