PAT A1050 String Subtraction

PAT A1050 String Subtraction

题目描述：

　　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.

参考代码：

/****************************************************
PAT A1050 String Subtraction
****************************************************/
#include <iostream>
#include <string>
#include <vector>

using namespace std;

int main() {
    string str1, str2;

    vector<bool> Hash(500, false);

    getline(cin, str1);
    getline(cin, str2);

    for (int i = 0; i < str2.size(); ++i) {
        Hash[str2[i]] = true;
    }

    for (int i = 0; i < str1.size(); ++i) {
        if (Hash[str1[i]] == false) {
            cout << str1[i];
        }
    }

    return 0;
}

注意事项：

　　无。