day two

2nd_day/1/input.txt

@@ -0,0 +1 @@
+5542145-5582046,243-401,884211-917063,1174-1665,767028-791710,308275-370459,285243789-285316649,3303028-3361832,793080-871112,82187-123398,7788-14096,21-34,33187450-33443224,2750031-2956556,19974-42168,37655953-37738891,1759-2640,55544-75026,9938140738-9938223673,965895186-966026269,502675-625082,11041548-11204207,1-20,3679-7591,8642243-8776142,40-88,2872703083-2872760877,532-998,211488-230593,3088932-3236371,442734-459620,8484829519-8484873271,5859767462-5859911897,9987328-10008767,656641-673714,262248430-262271846

2nd_day/1/main.cpp

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+#include <fstream>
+#include <iostream>
+#include <numeric>
+#include <set>
+#include <string>
+#include <vector>
+
+using namespace std;
+
+vector<string> get_input_from_file(const string file_name) {
+  ifstream file(file_name);
+  string input;
+  getline(file, input);
+  input += ",";
+
+  size_t pos;
+  vector<string> ids;
+
+  while ((pos = input.find(",")) != string::npos) {
+    if (pos == 0) {
+      input.erase(0, 1);
+      continue;
+    }
+    string id = input.substr(0, pos);
+    ids.push_back(id);
+    input.erase(0, pos + 1);
+  }
+
+  file.close();
+
+  return ids;
+}
+
+bool is_id_valid(string id) {
+  int len = id.length();
+  if (len % 2 != 0) {
+    return true;
+  }
+
+  string first_half = id.substr(0, len / 2);
+  string second_half = id.substr(len / 2);
+
+  if (first_half == second_half) {
+    cout << "Id " << id << " is not valid!" << endl;
+    return false;
+  }
+
+  return true;
+}
+
+set<string> get_invalid_ids(const string range) {
+  const size_t delimeter_pos = range.find("-");
+  const int length = range.length();
+
+  const long long start = stoll(range.substr(0, delimeter_pos));
+  const long long end = stoll(range.substr(delimeter_pos + 1));
+
+  set<string> invalid_ids;
+
+  for (long long id = start; id <= end; id++) {
+    if (!is_id_valid(to_string(id))) {
+      invalid_ids.insert(to_string(id));
+    }
+  }
+  return invalid_ids;
+}
+
+int main() {
+  const string FILE_NAME = "input.txt";
+  vector<string> ids = get_input_from_file(FILE_NAME);
+
+  set<string> all_invalid_ids;
+
+  for (string id : ids) {
+    set<string> invalid = get_invalid_ids(id);
+    all_invalid_ids.insert(invalid.begin(), invalid.end());
+  }
+  cout << "Ammount of invalid ids: "
+       << accumulate(all_invalid_ids.begin(), all_invalid_ids.end(), 0) << endl;
+}

2nd_day/1/test.txt

@@ -0,0 +1 @@
+11-22,95-115,998-1012,1188511880-1188511890,222220-222224,1698522-1698528,446443-446449,38593856-38593862,565653-565659,824824821-824824827,2121212118-2121212124

2nd_day/2/input.txt

@@ -0,0 +1 @@
+5542145-5582046,243-401,884211-917063,1174-1665,767028-791710,308275-370459,285243789-285316649,3303028-3361832,793080-871112,82187-123398,7788-14096,21-34,33187450-33443224,2750031-2956556,19974-42168,37655953-37738891,1759-2640,55544-75026,9938140738-9938223673,965895186-966026269,502675-625082,11041548-11204207,1-20,3679-7591,8642243-8776142,40-88,2872703083-2872760877,532-998,211488-230593,3088932-3236371,442734-459620,8484829519-8484873271,5859767462-5859911897,9987328-10008767,656641-673714,262248430-262271846

2nd_day/2/main.cpp

@@ -0,0 +1,73 @@
+#include <fstream>
+#include <iostream>
+#include <set>
+#include <string>
+#include <vector>
+
+using namespace std;
+
+vector<string> get_input_from_file(const string file_name) {
+  ifstream file(file_name);
+  string input;
+  getline(file, input);
+  input += ",";
+
+  size_t pos;
+  vector<string> ids;
+
+  while ((pos = input.find(",")) != string::npos) {
+    if (pos == 0) {
+      input.erase(0, 1);
+      continue;
+    }
+    string id = input.substr(0, pos);
+    ids.push_back(id);
+    input.erase(0, pos + 1);
+  }
+
+  file.close();
+
+  return ids;
+}
+
+bool is_id_periodic(string id) {
+  if (id.size() < 2)
+    return false;
+  return (id + id).find(id, 1) < id.size();
+}
+
+vector<string> get_invalid_ids(const string range) {
+  const size_t delimeter_pos = range.find("-");
+  const int length = range.length();
+
+  const long long start = stoll(range.substr(0, delimeter_pos));
+  const long long end = stoll(range.substr(delimeter_pos + 1));
+
+  vector<string> periodic_ids;
+
+  for (long long id = start; id <= end; id++) {
+    if (is_id_periodic(to_string(id))) {
+      periodic_ids.push_back(to_string(id));
+    }
+  }
+  return periodic_ids;
+}
+
+int main() {
+  const string FILE_NAME = "input.txt";
+  vector<string> ids = get_input_from_file(FILE_NAME);
+
+  set<string> all_periodc_ids;
+
+  for (string id : ids) {
+    vector<string> invalid = get_invalid_ids(id);
+    all_periodc_ids.insert(invalid.begin(), invalid.end());
+  }
+
+  long long sum = 0;
+  for (string id : all_periodc_ids) {
+    sum += stoll(id);
+  }
+
+  cout << "Sum of invalid ids: " << sum << endl;
+}

2nd_day/2/test.txt

@@ -0,0 +1 @@
+11-22,95-115,998-1012,1188511880-1188511890,222220-222224,1698522-1698528,446443-446449,38593856-38593862,565653-565659,824824821-824824827,2121212118-2121212124