Given two strings, find the number of common characters between them.

Example

For s1 = "aabcc" and s2 = "adcaa", the output should be
commonCharacterCount(s1, s2) = 3.

Strings have 3 common characters - 2 "a"s and 1 "c".

我的解答：

 def commonCharacterCount(s1, s2):

     sum = 0

     for i in set(s1):

         m = min(s1.count(i),s2.count(i))

         sum += m

     return sum

想了半天才想出来用set，知识都知道，但就是想不起来用，还是练得少啊

膜拜大佬：

一位美国大佬写的(排名靠前的基本都是这么写...)：

def commonCharacterCount(s1, s2):

    return sum(min(s1.count(x), s2.count(x)) for x in set(s1))