Actualize un poco las soluciones en c++ por aprender cositas

2020/day_2/password_philosophy.cc

@@ -0,0 +1,54 @@
+#include <algorithm>
+#include <iostream>
+#include <sstream>
+#include <fstream>
+#include <regex>
+#include <vector>
+#include <string>
+
+struct tokenized {
+  int first;
+  int second;
+  char letter;
+  std::string password; 
+};
+
+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;
+}
+
+tokenized parse_line(std::string &s) {
+  std::smatch match;
+  std::regex regex = std::regex("(.+)-(.+) (.): (.+)");
+  std::regex_search(s, match, regex);
+
+  return {stoi(match.str(1)), stoi(match.str(2)), match.str(3)[0], match.str(4)};
+}
+
+int main(){
+  auto data = read_input_file();
+
+  int result_a = 0;
+  int result_b = 0;
+
+  for(auto &line: data) {
+    auto t = parse_line(line);
+    int count = std::count(t.password.begin(), t.password.end(), t.letter);
+
+    if(t.first <= count && count <= t.second) 
+      result_a++;
+    if((t.password[t.first - 1] == t.letter) ^ (t.password[t.second - 1] == t.letter)) 
+      result_b++;
+  }
+
+  std::cout << result_a << ' ' << result_b << std::endl;
+
+  return 0;
+}