题解 | #字符串加密#

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

int main() {
    string key, str;
    while (cin >> key >> str) {
        // true代表未出现过
        string new_key;
        vector<bool> flag(26,true);
        // 对密钥key去重，生成短密钥new_key
        for (auto &i:key){
            i = tolower(i);
            if (flag[i - 'a']){
                // 一旦出现了，标记为false
                flag[i - 'a'] = false;
                new_key.push_back(i);
            }
        }
        // 补充密钥，生成字母表
        string table = "abcdefghijklmnopqrstuvwxyz";
        for (auto &i :table){
            if (flag[i - 'a']){
                new_key.push_back(i);
            }
        }
        string ciphertext = "";
        for (auto &i:str){
            ciphertext.push_back(new_key[i - 'a']);
        }
        cout << ciphertext;
    }
    return 0;
}