2023 Day 15

2023/puzzle-15-01.cc

@@ -0,0 +1,45 @@
+#include <cstdint>
+#include <cstdlib>
+#include <iostream>
+#include <string>
+#include <string_view>
+
+using UInt = std::uint64_t;
+
+auto hash(std::string_view const str) -> std::uint8_t
+{
+  std::uint8_t hash{0};
+  for (auto const c : str) {
+    hash += static_cast<std::uint8_t>(c);
+    hash += hash << 4;
+  }
+
+  return hash;
+}
+
+auto main() -> int try {
+  std::string line;
+  UInt total_hash{0};
+
+  if (!std::getline(std::cin, line)) {
+    std::cerr << "Unable to read input.";
+  }
+
+  std::size_t pos{0};
+  while (pos < line.size()) {
+    auto next_pos = line.find(',', pos);
+    if (next_pos == std::string::npos) { next_pos = line.size(); }
+    auto const h = hash(line.substr(pos, next_pos - pos));
+    std::cout << line.substr(pos, next_pos - pos) << ": " << static_cast<unsigned>(h) << '\n';
+    total_hash += h;
+    pos = next_pos + 1;
+  }
+
+  std::cout << "Total: " << total_hash << '\n';
+
+  return EXIT_SUCCESS;
+}
+catch (...) {
+  std::cerr << "Uncaught exception.\n";
+  return EXIT_FAILURE;
+}