1050. String Subtraction (20)

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<cstdio>
#include<cstring>
const int maxn = 10010;
char a[maxn],b[maxn];
bool hashTable[128] = {false};
int main(){
    gets(a);
    gets(b);
    int len1 = strlen(a);
    int len2 = strlen(b);
    for(int i = 0; i < len2; i++){
        hashTable[b[i]] = true;
    }
    for(int i = 0; i < len1; i++){
        if(hashTable[a[i]] == false){
            printf("%c",a[i]);
        }
    }
    return 0;
}