Its cute how the c++ version of day 5 is shorter

2020/day_5/binary_boarding.cc

@@ -0,0 +1,44 @@
+#include <algorithm>
+#include <vector>
+#include <set>
+#include <string>
+#include <fstream>
+#include <iostream>
+
+std::vector<std::string> read_input_file() {
+  std::ifstream file("input");
+  std::vector<std::string> data;
+  std::string line;
+
+  while(std::getline(file, line)) 
+    data.push_back(line);
+
+  return data;
+}
+
+int parse_id(std::string ticket) {
+  std::replace(ticket.begin(), ticket.end(), 'F', '0');
+  std::replace(ticket.begin(), ticket.end(), 'L', '0');
+  std::replace(ticket.begin(), ticket.end(), 'B', '1');
+  std::replace(ticket.begin(), ticket.end(), 'R', '1');
+
+  return stoi(ticket, nullptr, 2);
+}
+
+int solve_a(const std::set<int> &ids) { return *ids.rbegin(); }
+
+int solve_b(const std::set<int> &ids) {
+  for(int id = 0; id < 1024; id++)
+    if(!ids.contains(id) && ids.contains(id+1) && ids.contains(id-1))
+      return id;
+
+  return 0;
+}
+
+int main() {
+  std::set<int> ids;
+  for(auto &ticket: read_input_file()) ids.insert(parse_id(ticket));
+  std::cout << solve_a(ids) << " " << solve_b(ids) << std::endl;
+
+  return 0;
+}