Initial commit

2020/puzzle-14-01.cc

@@ -0,0 +1,68 @@
+#include <algorithm>
+#include <array>
+#include <cassert>
+#include <iostream>
+#include <list>
+#include <map>
+#include <regex>
+#include <string>
+
+using Data = std::uint64_t;
+using Mem = std::vector<Data>;
+
+struct Computer {
+  Computer() : set_(0), clear_(0), mem_() {}
+
+  void add_instruction(std::string const &s) {
+    static const std::regex re("mem\\[(\\d+)\\] = (\\d+)");
+    std::smatch m;
+
+    if (s.substr(0, 4) == "mask") {
+      set_ = 0;
+      clear_ = 0;
+      for (auto c : s.substr(7)) {
+        set_ <<= 1;
+        clear_ <<= 1;
+        set_ |= (c == '1');
+        clear_ |= (c != '0');
+      }
+      std::cout << "mask set: " << std::hex << set_ << "\n";
+      std::cout << "mask clear: " << std::hex << clear_ << "\n";
+    } else if (std::regex_search(s, m, re)) {
+      Data loc = std::stoul(m.str(1));
+      Data value = std::stoul(m.str(2));
+      std::cout << "mem[" << std::dec << loc << " = (" << value << " | " << set_
+                << ") & " << clear_ << " = ";
+      value = (value | set_) & clear_;
+      std::cout << value << "\n";
+      if (mem_.size() <= loc) {
+        mem_.resize(loc + 1, 0);
+      }
+      mem_[loc] = value;
+    }
+  }
+
+  Data mem_sum() const noexcept {
+    Data r = 0;
+    for (auto v : mem_) {
+      r += v;
+    }
+    return r;
+  }
+
+  Data set_;
+  Data clear_;
+  Mem mem_;
+};
+
+int main(int argc, char **argv) {
+  Computer c;
+
+  std::string line;
+  while (std::getline(std::cin, line)) {
+    c.add_instruction(line);
+  }
+
+  std::cout << "Memory sum: " << std::dec << c.mem_sum() << "\n";
+  return 0;
+}