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 + 10;

string s1, s2;
int book[MAX] = {0}, len1, len2;

int main()
{
//    freopen("Date1.txt", "r", stdin);
    getline(cin, s1);
    getline(cin, s2);
    len1 = s1.size(), len2 = s2.size();
    for (int i = 0; i < len2; ++ i) book[s2[i]] = 1;
    for (int i = 0; i < len1; ++ i)
        if (!book[s1[i]])
            printf("%c", s1[i]);
    return 0;
}