14

14/CMakeLists.txt

@@ -0,0 +1,22 @@
+cmake_minimum_required(VERSION 3.10)
+set(CMAKE_CXX_STANDARD 14)
+set(CMAKE_CXX_STANDARD_REQUIRED True)
+set(CMAKE_EXPORT_COMPILE_COMMANDS ON)
+enable_language(CXX)
+
+project(AoC14)
+
+if(APPLE)
+    include_directories(/usr/local/include)
+    link_directories(/usr/local/lib)
+endif()
+
+if(WIN32)
+	add_executable(${CMAKE_PROJECT_NAME} WIN32)
+else()
+	add_executable(${CMAKE_PROJECT_NAME})
+endif()
+
+target_sources(${CMAKE_PROJECT_NAME}
+	PRIVATE main.cpp
+	)

14/input

@@ -0,0 +1,102 @@
+SHPPPVOFPBFCHHBKBNCV
+
+HK -> C
+SP -> H
+VH -> K
+KS -> B
+BC -> S
+PS -> K
+PN -> S
+NC -> F
+CV -> B
+SH -> K
+SK -> H
+KK -> O
+HO -> V
+HP -> C
+HB -> S
+NB -> N
+HC -> K
+SB -> O
+SN -> C
+BP -> H
+FC -> V
+CF -> C
+FB -> F
+VP -> S
+PO -> N
+HN -> N
+BS -> O
+NF -> H
+BH -> O
+NK -> B
+KC -> B
+OS -> S
+BB -> S
+SV -> K
+CH -> B
+OB -> K
+FV -> B
+CP -> V
+FP -> C
+VC -> K
+FS -> S
+SS -> F
+VK -> C
+SF -> B
+VS -> B
+CC -> P
+SC -> S
+HS -> K
+CN -> C
+BN -> N
+BK -> B
+FN -> H
+OK -> S
+FO -> S
+VB -> C
+FH -> S
+KN -> K
+CK -> B
+KV -> P
+NP -> P
+CB -> N
+KB -> C
+FK -> K
+BO -> O
+OV -> B
+OC -> B
+NO -> F
+VF -> V
+VO -> B
+FF -> K
+PP -> O
+VV -> K
+PC -> N
+OF -> S
+PV -> P
+PB -> C
+KO -> V
+BF -> N
+OO -> K
+NV -> P
+PK -> V
+BV -> C
+HH -> K
+PH -> S
+OH -> B
+HF -> S
+NH -> H
+NN -> K
+KF -> H
+ON -> N
+PF -> H
+CS -> H
+CO -> O
+SO -> K
+HV -> N
+NS -> N
+KP -> S
+OP -> N
+KH -> P
+VN -> H

14/main.cpp

@@ -0,0 +1,102 @@
+#include <algorithm>
+#include <deque>
+#include <fstream>
+#include <iostream>
+#include <sstream>
+#include <unordered_map>
+#include <unordered_set>
+#include <vector>
+
+using Rules =
+    std::unordered_map<std::string, std::pair<std::string, std::string>>;
+using Growth =
+    std::unordered_map<std::string, std::unordered_map<char, uint64_t>>;
+
+std::pair<std::string, Rules> getRules(const std::string &file_name) {
+    Rules rules{};
+    std::string input{};
+
+    std::ifstream file(file_name);
+    std::string str;
+    bool isFold = false;
+    std::getline(file, input);
+    std::getline(file, str);
+    while (std::getline(file, str)) {
+        auto in = str.substr(0, 2);
+        auto mid = str.substr(6, 1);
+        rules[in] = { in[0] + mid, mid + in[1] };
+    }
+    return { input, rules };
+}
+
+uint64_t calculateDifferenceAfterRounds(const Rules &rules,
+                                        const std::string &text, int rounds) {
+    std::unordered_map<std::string, uint64_t> pair_count{};
+    for (auto &rule : rules) {
+        pair_count[rule.first] = 0;
+    }
+    for (int i = 0; i < text.size() - 1; i++) {
+        pair_count[text.substr(i, 2)] += 1;
+    }
+    for (int i = 0; i < rounds; i++) {
+        std::unordered_map<std::string, uint64_t> new_pair_count{};
+        for (auto &rule : rules) {
+            new_pair_count[rule.first] = 0;
+        }
+        for (auto &pair : pair_count) {
+            auto new_pairs = rules.at(pair.first);
+            new_pair_count[new_pairs.first] += pair.second;
+            new_pair_count[new_pairs.second] += pair.second;
+        }
+        pair_count = new_pair_count;
+    }
+
+    std::unordered_map<char, uint64_t> char_count{};
+    for (auto &pair : pair_count) {
+        char c = pair.first[0];
+        if (char_count.find(c) == char_count.end()) {
+            char_count[c] = pair.second;
+        } else {
+            char_count[c] += pair.second;
+        }
+    }
+    char_count[text.back()] += 1;
+
+    uint64_t min = -1, max = 0;
+    for (auto &c : char_count) {
+        if (c.second < min) {
+            min = c.second;
+        }
+        if (c.second > max) {
+            max = c.second;
+        }
+    }
+    return max - min;
+}
+
+uint64_t part1(Rules &rules, const std::string &text) {
+    return calculateDifferenceAfterRounds(rules, text, 10);
+}
+
+uint64_t part2(Rules &rules, const std::string &text) {
+    return calculateDifferenceAfterRounds(rules, text, 40);
+}
+
+int main(int argc, char **argv) {
+    if (argc < 2) {
+        std::cerr << "You must provide input file!" << std::endl;
+        return 1;
+    }
+    auto text_and_rules = getRules(argv[1]);
+    auto &text = text_and_rules.first;
+    auto &rules = text_and_rules.second;
+
+    std::cout << "The difference between the most common and least common "
+                 "letters after 10 rounds is \033[91;1m"
+              << part1(rules, text) << "\033[0m." << std::endl;
+
+    std::cout << "The difference between the most common and least common "
+                 "letters after 40 rounds is \033[91;1m"
+              << part2(rules, text) << "\033[0m." << std::endl;
+    return 0;
+}