题解 | #字符串加密#

#include <iostream>
#include <string>
#include <map>
#include <unordered_set>
using namespace std;

int main(int argc, char* argv[]){
    string key;
    cin >> key;
    string code;
    cin >> code;

    unordered_set<char> occ;
    auto iter = key.begin();
    while(iter != key.end()){
        if(occ.count(*iter)){
            iter = key.erase(iter);
        }
        else{
            occ.insert(*iter);
            ++iter;
        }
    }

    map<char, char> dic;
    for(int i = 0; i < key.size(); ++i){
        dic['a' + i] = key[i];
    }
    for(int i = key.size(); i < 26; ++i){
        int j = 0;
        while(occ.count('a' + j)){
            ++j;
        }
        dic['a' + i] = 'a' + j;
        occ.insert('a' + j);
    }

    for(int i = 0; i < code.size(); ++i){
        cout << dic[code[i]];
    }
    cout << endl;

    return 0;
}