pat 1050 String Subtraction（20 分）

1050 String Subtraction（20 分）

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

Sample Output:

Thy r stdnts.

 #include <iostream>
 #include <algorithm>
 #include <cstdio>
 #include <cstring>
 #include <map>
 #include <stack>
 #include <vector>
 #include <queue>
 #include <set>
 #define LL long long
 using namespace std;
 const int MAX = 1e4 + ;

 string s1, s2;
 int book[MAX] = {}, len1, len2;

 int main()
 {
 //    freopen("Date1.txt", "r", stdin);
     getline(cin, s1);
     getline(cin, s2);
     len1 = s1.size(), len2 = s2.size();
     for (int i = ; i < len2; ++ i) book[s2[i]] = ;
     for (int i = ; i < len1; ++ i)
         if (!book[s1[i]])
             printf("%c", s1[i]);
     return ;
 }