1050 String Subtraction（20 分）

#include
#include
#include
using namespace std;
string s1, s2;
bool hashtable[256];
int main()
{
    getline(cin, s1);
    getline(cin, s2);
    for (int i = 0; i < s2.length(); i++)hashtable[s2[i]] = true;
    for (int i = 0; i < s1.length(); i++)
    {
        if (hashtable[s1[i]])continue;
        printf("%c", s1[i]);
    }
    return 0;
}