74 lines
1.8 KiB
C++
74 lines
1.8 KiB
C++
#include <iomanip>
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#include <iostream>
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#include <numeric>
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#include <string>
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#include <vector>
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using UInt = unsigned char;
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using String = std::vector<UInt>;
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auto knot(String const& in, UInt current_position, UInt length) -> String
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{
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String rot_left;
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rot_left.reserve(in.size());
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std::copy(in.begin() + current_position, in.end(), std::back_inserter(rot_left));
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std::copy(in.begin(), in.begin() + current_position, std::back_inserter(rot_left));
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std::reverse(rot_left.begin(), rot_left.begin() + length);
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String rot_right;
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std::copy(rot_left.end() - current_position, rot_left.end(), std::back_inserter(rot_right));
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std::copy(rot_left.begin(), rot_left.end() - current_position, std::back_inserter(rot_right));
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return rot_right;
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}
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auto main() -> int
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{
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std::vector<UInt> string;
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string.resize(256);
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std::iota(string.begin(), string.end(), 0);
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std::string line;
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if (!std::getline(std::cin, line)) {
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std::cerr << "Unable to read line.\n";
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return 1;
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}
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/* Put the lengths into a vector. */
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std::vector<UInt> lengths;
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lengths.reserve(line.size() + 5);
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for (auto c : line) {
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lengths.emplace_back(static_cast<UInt>(c));
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}
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lengths.emplace_back(17);
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lengths.emplace_back(31);
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lengths.emplace_back(73);
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lengths.emplace_back(47);
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lengths.emplace_back(23);
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/* Run the hash */
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UInt current_pos{0};
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UInt skip{0};
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for (unsigned i{0}; i < 64; ++i) {
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for (auto length : lengths) {
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string = knot(string, current_pos, length);
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current_pos += length + skip;
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++skip;
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}
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}
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/* Print the dense hash. */
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std::cout << "Dense hash: ";
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unsigned hash{0};
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for (unsigned i{0}; i < string.size(); ++i) {
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hash ^= string[i];
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if (i % 16 == 15) {
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std::cout << std::hex << std::setw(2) << std::setfill('0') << hash;
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hash = 0;
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}
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}
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std::cout << '\n';
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return 0;
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}
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