PAT甲级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.

      题目大意：

         给出两个字符串，要求在第一个字符串中，删除掉第二个字符串中含有的字符。

 

思路：

         由于可能有空格，所以用getline（cin， s）， 那么枚举第二个字符串中每一个位置，逐一删除即可

 

参考代码：

#include<iostream>
#include<string>
using namespace std;
string s1, s2;
int main(){
	getline(cin, s1), getline(cin, s2);
	for(int i = 0; i < s2.size(); ++i){
		int post = s1.find(s2[i]);
		while(post != -1){
			s1.erase(post, 1);
			post = s1.find(s2[i]);
		}	
	}
	cout << s1;
	return 0;
}