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.

题意

给定两个字符串，S1 和 S2,要求将 S2 中的字符从 S1 串中剔除。

分析

用 Hash 的方式标记需要剔除的字符。

#include <iostream>

#include <cstdio>

#include <string>

using namespace std;

int main()

{

    int hs[] ={};

    char cs[];

    gets(cs);

    string st = cs;

    //getline(cin, st);

    while () {

        char c = getchar();

        if (c == '\n') break;

        hs[c] = ;

    }

    for (int i=; i<st.size(); i++) {

        if (hs[st[i]] == )

            printf("%c", st[i]);

    }

    return ;

}