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.

 比较简单的一道题目，利用string库可以很快解决。

#include<iostream>
#include<string>
using namespace std;

int main()
{
	string s1, s2;
	getline(cin, s1);
	getline(cin, s2);
	
	for (int i = 0; i < s1.length(); i++)
	{
		if (s2.find(s1[i]) == s2.npos)
		{
			cout << s1[i];
		}
	}
	cout << endl;
	return 0;
}