From 0b06899b68b52bbf8762a13bdb7c92b5786b35cb Mon Sep 17 00:00:00 2001
From: Matthew Gretton-Dann <matt@gretton-dann.org.uk>
Date: Mon, 5 Dec 2022 07:35:09 +0000
Subject: [PATCH] Add 2022 Day 5.

---
 2022/puzzle-05-01.cc | 67 ++++++++++++++++++++++++++++++++++++++++++++
 2022/puzzle-05-02.cc | 66 +++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 133 insertions(+)
 create mode 100644 2022/puzzle-05-01.cc
 create mode 100644 2022/puzzle-05-02.cc

diff --git a/2022/puzzle-05-01.cc b/2022/puzzle-05-01.cc
new file mode 100644
index 0000000..b20c1ce
--- /dev/null
+++ b/2022/puzzle-05-01.cc
@@ -0,0 +1,67 @@
+//
+// Created by Matthew Gretton-Dann on 05/12/2021.
+//
+
+#include <iostream>
+#include <regex>
+#include <string>
+#include <vector>
+
+using UInt = std::uint64_t;
+
+auto main() -> int
+{
+  std::string line;
+  std::vector<std::string> stacks(11, "");
+  while (std::getline(std::cin, line) && !line.empty()) {
+    UInt col{1};
+    UInt c4{0};
+    for (auto c : line) {
+      ++c4;
+      if (c4 == 4) {
+        ++col;
+        c4 = 0;
+      }
+      else if (std::isupper(c) == 1) {
+        stacks[col].push_back(c);
+      }
+    }
+  }
+
+  std::cout << "Initial stacks:\n";
+  for (auto const& s : stacks) {
+    std::cout << s << '\n';
+  }
+
+  while (std::getline(std::cin, line)) {
+    static std::regex const re{R"(move (\d+) from (\d+) to (\d+))"};
+    std::smatch m;
+    if (!std::regex_search(line, m, re)) {
+      std::cerr << "Unable to interpret: " << line << "\n";
+      return EXIT_FAILURE;
+    }
+    UInt const num{std::stoull(m.str(1))};
+    UInt const from{std::stoull(m.str(2))};
+    UInt const to{std::stoull(m.str(3))};
+    assert(stacks[from].size() >= num);
+    auto s = stacks[from].substr(0, num);
+    std::reverse(s.begin(), s.end());
+    stacks[from] = stacks[from].substr(num);
+    stacks[to] = s + stacks[to];
+  }
+
+  std::cout << "Final stacks:\n";
+  for (auto const& s : stacks) {
+    std::cout << s << '\n';
+  }
+
+  std::cout << "Result: ";
+  for (auto s : stacks) {
+    if (!s.empty()) {
+      std::cout << s.front();
+    }
+  }
+  std::cout << '\n';
+
+  return 0;
+}
diff --git a/2022/puzzle-05-02.cc b/2022/puzzle-05-02.cc
new file mode 100644
index 0000000..abd98a4
--- /dev/null
+++ b/2022/puzzle-05-02.cc
@@ -0,0 +1,66 @@
+//
+// Created by Matthew Gretton-Dann on 05/12/2021.
+//
+
+#include <iostream>
+#include <regex>
+#include <string>
+#include <vector>
+
+using UInt = std::uint64_t;
+
+auto main() -> int
+{
+  std::string line;
+  std::vector<std::string> stacks(11, "");
+  while (std::getline(std::cin, line) && !line.empty()) {
+    UInt col{1};
+    UInt c4{0};
+    for (auto c : line) {
+      ++c4;
+      if (c4 == 4) {
+        ++col;
+        c4 = 0;
+      }
+      else if (std::isupper(c) == 1) {
+        stacks[col].push_back(c);
+      }
+    }
+  }
+
+  std::cout << "Initial stacks:\n";
+  for (auto const& s : stacks) {
+    std::cout << s << '\n';
+  }
+
+  while (std::getline(std::cin, line)) {
+    static std::regex const re{R"(move (\d+) from (\d+) to (\d+))"};
+    std::smatch m;
+    if (!std::regex_search(line, m, re)) {
+      std::cerr << "Unable to interpret: " << line << "\n";
+      return EXIT_FAILURE;
+    }
+    UInt const num{std::stoull(m.str(1))};
+    UInt const from{std::stoull(m.str(2))};
+    UInt const to{std::stoull(m.str(3))};
+    assert(stacks[from].size() >= num);
+    auto s = stacks[from].substr(0, num);
+    stacks[from] = stacks[from].substr(num);
+    stacks[to] = s + stacks[to];
+  }
+
+  std::cout << "Final stacks:\n";
+  for (auto const& s : stacks) {
+    std::cout << s << '\n';
+  }
+
+  std::cout << "Result: ";
+  for (auto s : stacks) {
+    if (!s.empty()) {
+      std::cout << s.front();
+    }
+  }
+  std::cout << '\n';
+
+  return 0;
+}