From 1fce1637670c682f76c384685dd91df741eb6534 Mon Sep 17 00:00:00 2001
From: Reimar <mail@reim.ar>
Date: Wed, 17 Dec 2025 12:28:48 +0100
Subject: [PATCH] Solve day 3 part 2

---
 day_3.cpp | 38 +++++++++++++++++++++-----------------
 1 file changed, 21 insertions(+), 17 deletions(-)

diff --git a/day_3.cpp b/day_3.cpp
index 5c441a9..6f9a1f3 100644
--- a/day_3.cpp
+++ b/day_3.cpp
@@ -5,31 +5,35 @@ int main()
 {
 	std::ifstream file("input.txt");
 
-	int joltage_sum = 0;
+	long long int joltage_sum = 0;
+	const int digit_count = 2; // Use 12 for part 2
 
 	std::string bank;
 	while (getline(file, bank)) {
-		int first_index;
-		for (int i = 9; i > 0; i--) {
-			char digit = i + 48;
+		int indices[digit_count];
 
-			first_index = bank.find(digit);
+		for (int digit_index = 0; digit_index < digit_count; digit_index++) {
+			for (int i = 9; i > 0; i--) {
+				char digit = i + 48;
 
-			if (first_index != bank.size() - 1 && first_index != std::string::npos)
-				break;
+				// Start from previous index
+				int start_pos = digit_index == 0 ? 0 : indices[digit_index - 1] + 1;
+
+				int index = bank.find(digit, start_pos);
+
+				if (index < bank.size() - digit_count + digit_index + 1 && index != std::string::npos) {
+					indices[digit_index] = index;
+					break;
+				}
+			}
 		}
 
-		int second_index;
-		for (int i = 9; i > 0; i--) {
-			char digit = i + 48;
-
-			second_index = bank.find(digit, first_index + 1);
-
-			if (second_index != std::string::npos)
-				break;
+		// Collect characters into a single number
+		std::string joltage_str;
+		for (int index : indices) {
+			joltage_str += bank[index];
 		}
-
-		int joltage = std::stoi(std::string { bank[first_index], bank[second_index] });
+		long long int joltage = std::stoll(joltage_str);
 
 		std::cout << joltage << std::endl;