PAT 1050. String Subtraction (20)

#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<iostream>
#include<vector>
#include<queue>
#include<algorithm>
using namespace std;
#define maxsize 10001
#define  MIN -10001

int main()
{

    char s1[maxsize],s2[maxsize];
    gets(s1);
    gets(s2);
    for(int i=0;s1[i]!='\0';i++)
        if(strchr(s2,s1[i])==NULL)
          printf("%c",s1[i]);
    printf("\n");


    return 0;
}