input: Write a python function to find the longest common prefix among an array of strings.
  assert longestCommonPrefix(["flower", "flow", "flight"]) == "fl"
  assert longestCommonPrefix(["dog", "racecar", "car"]) == ""
  assert longestCommonPrefix(["interstellar", "internet", "interval"]) == "inte"
output: def longestCommonPrefix(strs):
      if not strs:
          return ""
  
      shortest = min(strs, key=len)
      
      for i, char in enumerate(shortest):
          for other in strs:
              if other[i] != char:
                  return shortest[:i]
                  
      return shortest