# Write a function to find the longest common prefix string amongst an array of strings.
class Solution():
def longestCommonPrefix(self, x):
if not x:
return ""
prefix = x[0]
for i in range(1, len(x)):
while x[i][:len(prefix)] != prefix:
prefix = prefix[:-1]
return prefix
if __name__ == "__main__":
assert Solution().longestCommonPrefix(["China", "Chinese", "Chipotle"]) == 'Chi'
assert Solution().longestCommonPrefix(["China", "", "Chipotle"]) == ''