【leetcode】389. Find the Difference【E】

Given two strings s and t which consist of only lowercase letters.

String t is generated by random shuffling string s and then add one more letter at a random position.

Find the letter that was added in t.

Example:

Input:
s = "abcd"
t = "abcde"

Output:
e

Explanation:
'e' is the letter that was added.

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最开始想都没想就用了set，结果肯定是不对的啊，因为集合会去重，要是有两个a，就变成一个a了

所以用字典，记录每个字母的个数

有一个小技巧，就是使用字典里面的get

还有就是检查的时候，使用try，这样就不用单独处理keyerror了

class Solution(object):
    def findTheDifference(self, s, t):

        dic_s = dict()
        dic_t = dict()

        for i in s:
            dic_s[i] = dic_s.get(i,0) + 1

        for i in t:
            dic_t[i] = dic_t.get(i,0) + 1

        for i in t:
            #print i
            try:
                if dic_t[i] != dic_s[i]:
                    return i

            except:
                return i


        """
        :type s: str
        :type t: str
        :rtype: str
        """