Add 2022 Day 7.

2022/puzzle-07-01.cc

@@ -0,0 +1,99 @@
+//
+// Created by Matthew Gretton-Dann on 07/12/2022.
+//
+
+#include <algorithm>
+#include <iostream>
+#include <list>
+#include <map>
+#include <numeric>
+#include <regex>
+#include <string>
+
+using UInt = std::uint64_t;
+
+struct DirectoryInfo
+{
+  auto total_size() const noexcept -> UInt
+  {
+    UInt file_size{std::accumulate(files_.begin(), files_.end(), UInt{0},
+                                   [](UInt a, auto const& b) { return a + b.second; })};
+    UInt directory_size{
+      std::accumulate(dirs_.begin(), dirs_.end(), UInt{0},
+                      [](UInt a, auto const& b) { return a + b.second.total_size(); })};
+    return file_size + directory_size;
+  }
+
+  auto find_dir(std::string const& name)
+  {
+    auto it{dirs_.find(name)};
+    assert(it != dirs_.end());
+    return it;
+  }
+
+  auto add_dir(std::string const& name) { dirs_.insert({name, DirectoryInfo()}); }
+
+  auto add_file(std::string const& name, UInt size) { files_.insert({name, size}); }
+
+  std::map<std::string, UInt> files_;
+  std::map<std::string, DirectoryInfo> dirs_;
+};
+
+using DirIt = std::map<std::string, DirectoryInfo>::iterator;
+
+auto count_dir_sizes(DirIt root, UInt max_size) -> UInt
+{
+  UInt result{0};
+  auto root_size = root->second.total_size();
+  if (root_size <= max_size) {
+    result += root_size;
+  }
+  for (auto it = root->second.dirs_.begin(); it != root->second.dirs_.end(); ++it) {
+    result += count_dir_sizes(it, max_size);
+  }
+  return result;
+}
+
+auto main() -> int
+{
+  UInt const max_size{100000};
+  std::string line;
+
+  std::list<DirIt> its;
+  std::map<std::string, DirectoryInfo> dirs;
+  auto root{dirs.insert({"/", DirectoryInfo()}).first};
+  while (std::getline(std::cin, line) && !line.empty()) {
+    if (line == "$ cd /") {
+      its.clear();
+      its.push_back(root);
+    }
+    else if (line == "$ cd ..") {
+      assert(!its.empty());
+      its.pop_back();
+    }
+    else if (line == "$ ls") {
+      continue;
+    }
+    else if (line.substr(0, 5) == "$ cd ") {
+      auto sub_dir{line.substr(5)};
+      assert(!its.empty());
+      auto it{its.back()->second.find_dir(sub_dir)};
+      its.push_back(it);
+    }
+    else if (line.substr(0, 4) == "dir ") {
+      its.back()->second.add_dir(line.substr(4));
+    }
+    else {
+      static std::regex const re{R"((\d+) ([a-z]+))"};
+      std::smatch m;
+      if (!std::regex_search(line, m, re)) {
+        std::cerr << "Unable to interpret: " << line << "\n";
+        std::exit(1);
+      }
+      its.back()->second.add_file(m.str(2), std::stoul(m.str(1)));
+    }
+  }
+
+  std::cout << "Total sizes: " << count_dir_sizes(root, max_size) << '\n';
+  return 0;
+}

2022/puzzle-07-02.cc

@@ -0,0 +1,106 @@
+//
+// Created by Matthew Gretton-Dann on 07/12/2022.
+//
+
+#include <algorithm>
+#include <iostream>
+#include <list>
+#include <map>
+#include <numeric>
+#include <regex>
+#include <string>
+
+using UInt = std::uint64_t;
+
+struct DirectoryInfo
+{
+  auto total_size() const noexcept -> UInt
+  {
+    UInt file_size{std::accumulate(files_.begin(), files_.end(), UInt{0},
+                                   [](UInt a, auto const& b) { return a + b.second; })};
+    UInt directory_size{
+      std::accumulate(dirs_.begin(), dirs_.end(), UInt{0},
+                      [](UInt a, auto const& b) { return a + b.second.total_size(); })};
+    return file_size + directory_size;
+  }
+
+  auto find_dir(std::string const& name)
+  {
+    auto it{dirs_.find(name)};
+    assert(it != dirs_.end());
+    return it;
+  }
+
+  auto add_dir(std::string const& name) { dirs_.insert({name, DirectoryInfo()}); }
+
+  auto add_file(std::string const& name, UInt size) { files_.insert({name, size}); }
+
+  std::map<std::string, UInt> files_;
+  std::map<std::string, DirectoryInfo> dirs_;
+};
+
+using DirIt = std::map<std::string, DirectoryInfo>::iterator;
+
+auto size_to_free(DirIt root, UInt min) -> UInt
+{
+  UInt result{std::numeric_limits<UInt>::max()};
+
+  auto root_size = root->second.total_size();
+  if (root_size >= min) {
+    result = std::min(result, root_size);
+  }
+  for (auto it = root->second.dirs_.begin(); it != root->second.dirs_.end(); ++it) {
+    auto t{size_to_free(it, min)};
+    if (t >= min) {
+      result = std::min(result, t);
+    }
+  }
+  return result;
+}
+
+auto main() -> int
+{
+  std::string line;
+
+  std::list<DirIt> its;
+  std::map<std::string, DirectoryInfo> dirs;
+  auto root{dirs.insert({"/", DirectoryInfo()}).first};
+  while (std::getline(std::cin, line) && !line.empty()) {
+    if (line == "$ cd /") {
+      its.clear();
+      its.push_back(root);
+    }
+    else if (line == "$ cd ..") {
+      assert(!its.empty());
+      its.pop_back();
+    }
+    else if (line == "$ ls") {
+      continue;
+    }
+    else if (line.substr(0, 5) == "$ cd ") {
+      auto sub_dir{line.substr(5)};
+      assert(!its.empty());
+      auto it{its.back()->second.find_dir(sub_dir)};
+      its.push_back(it);
+    }
+    else if (line.substr(0, 4) == "dir ") {
+      its.back()->second.add_dir(line.substr(4));
+    }
+    else {
+      static std::regex const re{R"((\d+) ([a-z]+))"};
+      std::smatch m;
+      if (!std::regex_search(line, m, re)) {
+        std::cerr << "Unable to interpret: " << line << "\n";
+        return EXIT_FAILURE;
+      }
+      its.back()->second.add_file(m.str(2), std::stoul(m.str(1)));
+    }
+  }
+
+  UInt constexpr disk_size{70000000};
+  UInt constexpr needed_space{30000000};
+  UInt current_space{disk_size - root->second.total_size()};
+  UInt min_space_to_free(needed_space - current_space);
+  std::cout << "Size to free: " << size_to_free(root, min_space_to_free) << '\n';
+  return 0;
+}