题解 | #字符串加密#

#include<iostream>
#include<string>
#include<cmath>
using namespace std;

int main() 
{
    string alphabet = "abcdefghijklmnopqrstuvwxyz"; //普通26个字母表
    string key;                                     //密钥key
    string s;                                       //要加密的字符串s
    cin >> key;
    cin >> s;
    alphabet = key + alphabet;                      //首先直接将key拼接到字母表开头
    for (int i = 0; i < alphabet.size(); i++)       //然后遍历整个拼接后的字母表，每有字母重复出现，将该位置改为'0'
    {
        for (int j = 0; j < i; j++)
        {
            if (alphabet[i] == alphabet[j])
            {
                alphabet[i] = '0';
            }
        }
    }
    string newalph = "abcdefghijklmnopqrstuvwxyz";
    for (int i = 0,j=0; i < alphabet.size(); i++)   //将拼接后的字母表中所有不为'0'的部分按顺序存入新字母表newalph中
    {
        if (alphabet[i] != '0')
        {
            newalph[j] = alphabet[i];
            j++;
        }
    }
    for(int i = 0; i < s.size(); i++)               //按照新字母表newalph,加密字符串s
    {
        s[i] = newalph[s[i] - 'a'];
    }
    cout << s << endl;
    return 0;
}