1050 String Subtraction

Given two strings S₁ and S₂, S = S₁ - S₂ is defined to be the remaining string after taking all the characters in S₂ from S₁. Your task is simply to calculate S₁ - S₂ 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 S₁ and S₂, respectively. The string lengths of both strings are no more than 10⁴. 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 S₁ - S₂ in one line.

Sample Input:

They are students.aeiou

Sample Output:

Thy r stdnts.

#include<iostream>#include<string>using namespace std;int main(){for(string s1;getline(cin,s1);){string s2;getline(cin,s2);int flag[257]={0};for(int i = 0;i < s2.length();i++){flag[s2[i]] = 1;}for(int i = 0; i < s1.length();i++){if(!flag[s1[i]]){cout<<s1[i];}}cout<<endl;}return 0;}