String Subtraction (20)

本文介绍了一种计算两个字符串差集的算法实现,通过构建哈希表来高效地去除第二个字符串中包含的所有字符,最终输出第一个字符串中未被第二个字符串覆盖的部分。

摘要生成于 C知道 ,由 DeepSeek-R1 满血版支持, 前往体验 >

题目描述

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 - S2for any given strings. However, it might not be that simple to do it fast.

输入

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.

输出

For each test case, print S1 - S2 in one line.

样例输入

They are students.
aeiou

样例输出

Thy r stdnts.

#include <cstdio>
#include <cstring>
//将字符转换成整数
int charToNum(char a)
{
    int num = 0;
    if(a >= 'A' && a <= 'Z') num = a - 'A';
    else if(a >= 'a' && a <= 'z') num = a - 'a' + 26;
    return num;
}

int main()
{
    char str[10010];
    char del[10010];
    gets(str);
    gets(del);
    int len1 = strlen(str);
    int len2 = strlen(del);
    int hash[53] = {0};
    for(int i = 0;i < len1;i++)
    {
        if(str[i] != ' ' && str[i] != '.')
            hash[charToNum(str[i])] = 1;
    }
    for(int i = 0;i < len2;i++)
    {
        if(hash[charToNum(del[i])] == 1)
        {
            hash[charToNum(del[i])] = 0;
        }
    }
    for(int i = 0;i < len1;i++)
    {
        if(hash[charToNum(str[i])] == 1 || str[i] == ' ' || str[i] == '.') printf("%c",str[i]);
    }
    printf("\n");
    return 0;
}
评论
添加红包

请填写红包祝福语或标题

红包个数最小为10个

红包金额最低5元

当前余额3.43前往充值 >
需支付:10.00
成就一亿技术人!
领取后你会自动成为博主和红包主的粉丝 规则
hope_wisdom
发出的红包
实付
使用余额支付
点击重新获取
扫码支付
钱包余额 0

抵扣说明:

1.余额是钱包充值的虚拟货币,按照1:1的比例进行支付金额的抵扣。
2.余额无法直接购买下载,可以购买VIP、付费专栏及课程。

余额充值