From da62aa3d801b65b0985497cf110bfb2bdaf48ace Mon Sep 17 00:00:00 2001
From: cat <cat@thenight.club>
Date: Tue, 2 Dec 2025 22:09:19 +0200
Subject: [PATCH] Day 2 part 2

---
 Day2/Question2/input     |  1 +
 Day2/Question2/inputTest |  1 +
 Day2/Question2/main.cpp  | 70 ++++++++++++++++++++++++++++++++++++++++
 3 files changed, 72 insertions(+)
 create mode 100644 Day2/Question2/input
 create mode 100644 Day2/Question2/inputTest
 create mode 100644 Day2/Question2/main.cpp

diff --git a/Day2/Question2/input b/Day2/Question2/input
new file mode 100644
index 0000000..9352771
--- /dev/null
+++ b/Day2/Question2/input
@@ -0,0 +1 @@
+16100064-16192119,2117697596-2117933551,1-21,9999936269-10000072423,1770-2452,389429-427594,46633-66991,877764826-877930156,880869-991984,18943-26512,7216-9427,825-1162,581490-647864,2736-3909,39327886-39455605,430759-454012,1178-1741,219779-244138,77641-97923,1975994465-1976192503,3486612-3602532,277-378,418-690,74704280-74781349,3915-5717,665312-740273,69386294-69487574,2176846-2268755,26-45,372340114-372408052,7996502103-7996658803,7762107-7787125,48-64,4432420-4462711,130854-178173,87-115,244511-360206,69-86
diff --git a/Day2/Question2/inputTest b/Day2/Question2/inputTest
new file mode 100644
index 0000000..a3f22ef
--- /dev/null
+++ b/Day2/Question2/inputTest
@@ -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
diff --git a/Day2/Question2/main.cpp b/Day2/Question2/main.cpp
new file mode 100644
index 0000000..d78d033
--- /dev/null
+++ b/Day2/Question2/main.cpp
@@ -0,0 +1,70 @@
+#include <cmath>
+#include <cstdint>
+#include <fstream>
+#include <iostream>
+#include <ostream>
+#include <string>
+#include <sys/types.h>
+#include <vector>
+
+std::vector<uint64_t> findFactors(uint64_t number) {
+  // Technically acending order would be better than decending order for
+  // algorithm below
+  std::vector<uint64_t> factorList;
+  for (uint64_t possibleFactor = std::ceil(number / 2.0f); possibleFactor > 1;
+       possibleFactor--) {
+    if (number % possibleFactor == 0) {
+      factorList.push_back(possibleFactor);
+    }
+  }
+
+  // Certain that every whole number is divisble by 1 lol
+  factorList.push_back(1);
+  return factorList;
+}
+
+int main() {
+  std::fstream file("input");
+  std::string currentID = "", currentNumber = "", chunk = "";
+  uint64_t rangeMin = 0, rangeMax = 0, positionOfHypen = 0, numberOfDigits = 0,
+           sumOfAllInvalidIds = 0;
+  bool isInvalid = false;
+
+  while (std::getline(file, currentID, ',')) {
+    // I'm sure there is a better way to do this
+    positionOfHypen = currentID.find('-');
+    rangeMin = std::stoull(currentID.substr(0, positionOfHypen));
+    rangeMax = std::stoull(currentID.substr(positionOfHypen + 1));
+
+    // I'm not fan of the loops I've done here
+    for (uint64_t number = rangeMin; number <= rangeMax; number++) {
+      numberOfDigits = std::floor(std::log10(number)) + 1;
+
+      // Each factor of the total digits needs to be checked
+      for (uint64_t factor : findFactors(numberOfDigits)) {
+        currentNumber = std::to_string(number);
+        chunk = currentNumber.substr(0, factor);
+        isInvalid = false;
+
+        // Comparing chuncks to eachother
+        for (uint64_t index = factor; index < numberOfDigits; index += factor) {
+          isInvalid = chunk == currentNumber.substr(index, factor);
+
+          // Break if it is valid with these chunks
+          if (!isInvalid) {
+            break;
+          }
+        }
+
+        // Break if we proved thats invalid above
+        if (isInvalid) {
+          break;
+        }
+      }
+
+      sumOfAllInvalidIds += isInvalid ? number : 0;
+    }
+  }
+  std::cout << sumOfAllInvalidIds << std::endl;
+  return 0;
+}