Day 25 part1

Author: bt

CMakeLists.txt

@@ -30,6 +30,7 @@ add_challenge(day17)
 add_challenge(day18)
 add_challenge(day19)
 add_challenge(day24)
+add_challenge(day25)
 
 add_custom_command(TARGET day1
     COMMAND ${CMAKE_COMMAND} -E create_symlink "${CMAKE_CURRENT_SOURCE_DIR}/data" "./data"

src/day25.cpp

@@ -0,0 +1,124 @@
+#include "common_headers.hpp"
+
+using Heights = std::vector<size_t>;
+
+struct LocksAndKeys final
+{
+    size_t lockHeight{7};
+    std::vector<Heights> locks;
+    std::vector<Heights> keys;
+};
+
+
+[[nodiscard]] size_t solveFirstPart(const LocksAndKeys& locksAndKeys)
+{
+    size_t count{};
+    for(const auto& lock : locksAndKeys.locks) {
+        for(const auto& key : locksAndKeys.keys) {
+            if(lock.size() != key.size()) {
+                throw std::logic_error{"sizes of lock and key differ"};
+            }
+            bool fit{true};
+            for(size_t i = 0; i < lock.size(); ++i) {
+                fit = fit && (lock[i] + key[i] <= locksAndKeys.lockHeight);
+            }
+            count += fit;
+        }
+    }
+    return count;
+}
+
+[[nodiscard]] size_t parseHeights(const std::vector<std::string>& inputVec, size_t beginInputId, Heights& heights)
+{
+    size_t inputId{beginInputId};
+    heights.reserve(inputVec[0].size());
+    for(size_t column = 0; column < inputVec[0].size(); ++column) {
+        auto row = inputId;
+        size_t height{};
+        while(row < inputVec.size() && !inputVec[row].empty()) {
+            height += (inputVec[row][column] == '#');
+            ++row;
+        }
+        heights.push_back(height);
+    }
+
+    while(inputId < inputVec.size() && !inputVec[inputId].empty()) ++inputId;
+    ++inputId; //< skip empty line
+    return inputId;
+}
+
+[[nodiscard]] size_t parseLocks(const std::vector<std::string>& inputVec, size_t beginInputId, LocksAndKeys& locksAndKeys)
+{
+    size_t inputId{beginInputId};
+    while(inputId < inputVec.size() && inputVec[inputId][0] == '#') {
+        locksAndKeys.locks.emplace_back();
+        inputId = parseHeights(inputVec, inputId, locksAndKeys.locks.back());
+
+        if(locksAndKeys.locks.back().empty()) {
+            locksAndKeys.locks.back().pop_back();
+        }
+    }
+    return inputId;
+}
+
+[[nodiscard]] size_t parseKeys(const std::vector<std::string>& inputVec, size_t beginInputId, LocksAndKeys& locksAndKeys)
+{
+    size_t inputId{beginInputId};
+    while(inputId < inputVec.size() && inputVec[inputId][0] == '.') {
+        locksAndKeys.keys.emplace_back();
+        inputId = parseHeights(inputVec, inputId, locksAndKeys.keys.back());
+
+        if(locksAndKeys.keys.back().empty()) {
+            locksAndKeys.keys.back().pop_back();
+        }
+    }
+    return inputId;
+}
+
+[[nodiscard]] LocksAndKeys parseInput(const std::vector<std::string>& inputVec)
+{
+    LocksAndKeys locksAndKeys;
+    size_t inputId{};
+    while(inputId < inputVec.size()) {
+        inputId = parseLocks(inputVec, inputId, locksAndKeys);
+        inputId = parseKeys(inputVec, inputId, locksAndKeys);
+    }
+
+    return locksAndKeys;
+}
+
+void printHelp()
+{
+    std::cerr << "\nUsage:\n"
+    << "The program requires 2 args: (part1, part2) and the path to the file."
+    << "\nFor example, ./day7 part1 data/day7.txt";
+}
+
+int main(int argc, char* argv[])
+{
+    if(argc != 3) {
+        printHelp();
+        return 1;
+    }
+
+    std::string_view task{argv[1]};
+    if(task != "part1" && task != "part2") {
+        std::cerr << "\nfirst arg can be either `part1` or `part2`\n";
+        printHelp();
+        return 1;
+    }
+    
+    std::vector<std::string> inputVec;
+    readInput(argv[2], std::back_inserter(inputVec));
+
+    auto locksAndKeys = parseInput(inputVec);
+    
+    if(task == "part1") {
+        std::cout << solveFirstPart(locksAndKeys);
+    }
+    else {
+        // std::cout << solveSecondPart(program);       
+    }
+
+    return 0;
+}