class Solution:
  def findRange(self, arr, key):
    def find_first():
      b, e = 0, len(arr) - 1
      index = 0 
      while b <= e:
        m = (b + e) // 2 
        if arr[m] >= key:
          index = m
          e = m - 1
        else:
          b = m + 1
      return index

    def find_last():
      b, e = 0, len(arr) - 1
      index = 0 
      while b <= e:
        m = (b + e) // 2 
        if arr[m] <= key:
          index = m
          b = m + 1
        else:
          e = m - 1
      return index
    
    first = find_first()
    last = find_last()
   
    return [first if arr[first] == key else -1, last if arr[last] == key else -1]