389. Find the Difference
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.
class Solution:
def findTheDifference(self, s, t):
"""
:type s: str
:type t: str
:rtype: str
"""
if len(t)>len(s):
s,t = t,s
a = list(s)
b = {}
for i in t:
if i in b:
b[i] += 1
else:
b[i] = 1
for i in a:
if i not in b:
return i
if b[i]==0:
return i
b[i] -= 1