题目
Given two strings S 1 and S 2 , S=S 1 −S 2 is defined to be the remaining string after taking all the characters in S 2 from S 1 . Your task is simply to calculate S 1 −S 2 for any given strings. However, it might not be that simple to do it fast.
Input Specification: Each input file contains one test case. Each case consists of two lines which gives S 1 and S 2 , respectively. The string lengths of both strings are no more than 10 4 . It is guaranteed that all the characters are visible ASCII codes and white space, and a new line character signals the end of a string.
Output Specification: For each test case, print S 1 −S 2 in one line.
Sample Input:
They are students.
aeiou
结尾无空行
Sample Output:
Thy r stdnts.
结尾无空行
解题思路
S1 = list(input())
S2 = list(input())
# S1 = list("They are students.")
# S2 = list("aeiou")
#暴力法
# for i in S2:
# while True:
# try:
# S1.remove(i)
# except:
# break
# print("".join(S1))
#字典
S2Dict = dict()
for i in S2:
S2Dict[i] = 1
res = ""
for j in S1:
if j not in S2Dict:
res += j
print(res)
