f0615.cpp

it is a usefull thing

//==================================
// f0615.cpp
// 剩余串排列
//==================================
#include<iostream>
#include<fstream>
#include<algorithm>
using namespace std;
//----------------------------------
int main(){
  ifstream in("remainder.txt");
  for(string s,t,u; in>>s>>t; u=""){ 
    sort(s.begin(),s.end());
    sort(t.begin(),t.end());
    set_difference(s.begin(),s.end(),t.begin(),t.end(),back_inserter(u));
    cout<<u<<endl;
  }
}//=================================