VerticalPermutation

rgoerv

Apr 5th, 2025 (edited)

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#include <iostream>
#include <string>
#include <algorithm>
#include <vector>
#include <cstdint>
#include <unordered_map>
#include <cmath>
using namespace std::string_literals;
std::string VerticalPermutationENcode(const std::vector<int>& Key, const std::string& StrForENcoding)
{
std::unordered_map<int, std::string> ENCodeTable;
const std::vector<int> sortedKey = ([&Key]() {
std::vector<int> SortedKeyBuf(Key);
std::sort(SortedKeyBuf.begin(), SortedKeyBuf.end());
return SortedKeyBuf;
})();
size_t TableLen = Key.size();
size_t keyIdx = 0;
for(const int& key_part : sortedKey) {
std::string vertical;
for(size_t idx = keyIdx; idx < StrForENcoding.length(); idx += TableLen)
{
vertical.push_back(StrForENcoding[idx]);
}
ENCodeTable[key_part] = vertical;
++keyIdx;
}
std::string ENCodedStr;
for(const int& key_part : Key) {
ENCodedStr.append(ENCodeTable[key_part]);
}
return ENCodedStr;
}
static std::string VerticalPermutationDEcode(const std::vector<int>& Key, const std::string& StrForDEcoding)
{
const size_t str_size = StrForDEcoding.size();
const size_t TableLen = Key.size();
const size_t ver_max_size = ceil((double)str_size / (double)TableLen);
const size_t ver_res = (str_size % TableLen);
const std::vector<int> sortedKey = ([&Key]() {
std::vector<int> SortedKeyBuf(Key);
std::sort(SortedKeyBuf.begin(), SortedKeyBuf.end());
return SortedKeyBuf;
})();
std::unordered_map<int, std::string> SortedKeyToStrForDecode;
size_t len = 0;
size_t curr_len = ver_max_size;
for(size_t i = 0; i < TableLen; ++i, len += curr_len) {
curr_len = Key[i] <= ver_res ? ver_max_size : ver_max_size - 1;
SortedKeyToStrForDecode[Key[i]] = StrForDEcoding.substr(len, curr_len);
}
std::vector<std::string> strkey;
std::string decoded_str = ""s;
for(const auto& key : sortedKey) {
strkey.push_back(SortedKeyToStrForDecode[key]);
}
for(size_t i = 0; i < ver_max_size; ++i) {
for(auto& str : strkey) {
decoded_str.push_back(str[i]);
}
}
return decoded_str;
}
int main()
{
setlocale(LC_ALL, "");
static std::string str_for_encoding = "Пример работы шифра вертикальной перестановки"s;
std::vector<int> key = { 3, 1, 4, 5, 2 };
std::cout << str_for_encoding << std::endl;
std::string encoded_str = VerticalPermutationENcode(key, str_for_encoding);
std::cout << encoded_str << std::endl
<< VerticalPermutationDEcode(key, encoded_str) << std::endl;
}

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