move 2021 days to folder; update README

1 files changed, 0 insertions, 131 deletions

diff --git a/day16/part2.cpp b/day16/part2.cpp
deleted file mode 100644
index 5a02df9..0000000
--- a/day16/part2.cpp
+++ /dev/null
@@ -1,131 +0,0 @@
-#include <algorithm>
-#include <cstdint>
-#include <iostream>
-#include <list>
-#include <map>
-#include <string>
-#include <string_view>
-#include <tuple>
-
-static const std::map<char, const char *> hexToBin = {
-    {'0', "0000"}, {'1', "0001"}, {'2', "0010"}, {'3', "0011"},
-    {'4', "0100"}, {'5', "0101"}, {'6', "0110"}, {'7', "0111"},
-    {'8', "1000"}, {'9', "1001"}, {'A', "1010"}, {'B', "1011"},
-    {'C', "1100"}, {'D', "1101"}, {'E', "1110"}, {'F', "1111"}
-};
-
-static std::pair<uint64_t, std::string_view> solve(std::string_view packet);
-
-int main(int argc, const char *argv[])
-{
-    if (argc != 2)
-        return -1;
-
-    std::string packetBin;
-    std::string packetHex (argv[1]);
-    for (char c : packetHex)
-        packetBin += hexToBin.at(c);
-
-    std::cout << solve(packetBin).first << std::endl;
-
-    return 0;
-}
-
-uint64_t binStrToInt(std::string_view bin)
-{
-    uint64_t n = 0;
-
-    for (char c : bin) {
-        n = n * 2ull;
-        if (c == '1')
-            ++n;
-    }
-
-    return n;
-}
-
-bool isEmptyPacket(std::string_view packet)
-{
-    return packet.empty() ||
-           std::all_of(packet.cbegin(), packet.cend(),
-                       [](char c) { return c == '0'; });
-}
-
-std::pair<uint64_t, std::string_view> solve(std::string_view packet)
-{
-    // Remove version
-    packet = packet.substr(3);
-    // Pull type ID
-    const auto typeId = packet.substr(0, 3);
-    packet = packet.substr(3);
-    
-    if (typeId == "100") {
-        std::string numberStr;
-        while (1) {
-            const auto chunk = packet.substr(0, 5);
-            packet = packet.substr(5);
-            numberStr += chunk.substr(1);
-            if (chunk.front() == '0')
-                break;
-        }
-
-        return {binStrToInt(numberStr), isEmptyPacket(packet) ? "" : packet};
-    } else {
-        const bool isLengthBits = packet.front() == '0';
-        packet = packet.substr(1);
-        const auto lengthStr = packet.substr(0, isLengthBits ? 15 : 11);
-        const auto length = binStrToInt(lengthStr);
-        packet = packet.substr(isLengthBits ? 15 : 11);
-
-        std::list<uint64_t> args;
-        if (isLengthBits) {
-            auto rem = packet.substr(0, length);
-            while (1) {
-                const auto ret = solve(rem);
-                args.emplace_front(ret.first);
-                if (ret.second.empty() || isEmptyPacket(ret.second))
-                    break;
-                rem = ret.second;
-            }
-            packet = packet.substr(length);
-        } else {
-            for (uint64_t i = 0; i < length; ++i) {
-                const auto ret = solve(packet);
-                args.emplace_front(ret.first);
-                packet = ret.second;
-                if (isEmptyPacket(packet))
-                    break;
-            }
-        }
-
-        uint64_t result;
-        if (typeId == "000") {
-            result = 0;
-            for (auto a : args)
-                result += a;
-        } else if (typeId == "001") {
-            result = 1;
-            for (auto a : args)
-                result *= a;
-        } else if (typeId == "010") {
-            result = *std::min_element(args.cbegin(), args.cend());
-        } else if (typeId == "011") {
-            result = *std::max_element(args.cbegin(), args.cend());
-        } else if (typeId == "101") {
-            const auto a1 = args.back();
-            args.pop_back();
-            result = args.back() < a1;
-        } else if (typeId == "110") {
-            const auto a1 = args.back();
-            args.pop_back();
-            result = args.back() > a1;
-        } else if (typeId == "111") {
-            const auto a1 = args.back();
-            args.pop_back();
-            result = args.back() == a1;
-        }
-
-        return {result, isEmptyPacket(packet) ? "" : packet};
-    }
-}
-