From e3098c6651fd2ffa488b74e1c93349d8ef65df9b Mon Sep 17 00:00:00 2001
From: Feiko Wielsma <feiko.w@gmail.com>
Date: Thu, 4 Dec 2025 12:54:27 +0000
Subject: [PATCH] D3P2

---
 day3/main.cpp   | 78 ++++++++++++++++++++++++++++++++++++++++++++-----
 day3/test_input |  4 +--
 2 files changed, 72 insertions(+), 10 deletions(-)

diff --git a/day3/main.cpp b/day3/main.cpp
index c2a523d..aab3028 100644
--- a/day3/main.cpp
+++ b/day3/main.cpp
@@ -76,15 +76,77 @@ auto countJoltages(const std::vector<std::vector<int>>& banks) {
     return totalJoltage;
 }   
 
+auto calculateJoltageP2(const std::vector<int>& bank) -> long long{
+    const int TO_TAKE = 12;
+    std::vector<int> takenNumbers{};
+
+    auto curIt = bank.begin();
+    auto rightIt = bank.end();
+
+    auto leftBound = bank.begin();
+
+    while(takenNumbers.size() != TO_TAKE){
+       
+        // First find biggest number with that is not in the last 12
+        while(curIt != (rightIt +1 - TO_TAKE + takenNumbers.size())){
+            if(*curIt > *leftBound ){
+                leftBound = curIt;
+            }
+            curIt++; 
+        }
+        takenNumbers.push_back(*leftBound); 
+
+        curIt = leftBound+1;
+        leftBound = curIt;
+    }
+    
+    long long intRepr = std::ranges::fold_left(takenNumbers, 0, [](long long x, long long y) -> long long{
+        return (x*10) + y;
+    });
+    return intRepr;
+}
+
+auto calculateJoltageP2_Optimized(const std::vector<int>& bank) -> long long {
+    const int TO_TAKE = 12;
+    
+    if (bank.size() < TO_TAKE) { return 0; }
+
+    long long result = 0;
+    auto current_start = bank.begin();
+    
+    for (int i = 0; i < TO_TAKE; ++i) {
+
+        
+        int items_needed_after_this = (TO_TAKE - 1) - i;
+        auto search_end = bank.end() - items_needed_after_this;
+
+        auto max_it = std::max_element(current_start, search_end);
+
+        result = (result * 10) + *max_it;
+
+        current_start = max_it + 1;
+    }
+
+    return result;
+}
+
+auto countJoltagesP2(const std::vector<std::vector<int>>& banks) {
+    long totalJoltage{};
+    for(const auto& bank : banks){
+        totalJoltage += calculateJoltageP2_Optimized(bank);
+    }
+    return totalJoltage;
+}   
+
 auto main() -> int {
 
     
     auto testCase = parseBanks("test_input");
     if(testCase) {
-            auto testResult = countJoltages(*testCase);
-            // auto testResultP2 = countRepeats(*testCase);
-            std::println("P1 Testcase result: {}", testResult);
-            // std::println("P2 Testcase result: {}", testResultP2);
+            //auto testResult = countJoltages(*testCase);
+            auto testResultP2 = countJoltagesP2(*testCase);
+            //std::println("P1 Testcase result: {}", testResult);
+            std::println("P2 Testcase result: {}", testResultP2);
     }
     else{
         std::print("{}\n", testCase.error());    
@@ -93,10 +155,10 @@ auto main() -> int {
 
     auto realPuzzle = parseBanks("puzzle_input");
     if(realPuzzle) {
-            auto realResult = countJoltages(*realPuzzle);
-            // auto realResultP2 = countRepeats(*realRanges);
-            std::println("P1 Real result: {}", realResult);
-            // std::println("P2 Real result: {}", realResultP2);
+            //auto realResult = countJoltages(*realPuzzle);
+            auto realResultP2 = countJoltagesP2(*realPuzzle);
+            //std::println("P1 Real result: {}", realResult);
+            std::println("P2 Real result: {}", realResultP2);
     }
     else{
         std::print("{}\n", realPuzzle.error());    
diff --git a/day3/test_input b/day3/test_input
index 6b1df6a..a7353bc 100644
--- a/day3/test_input
+++ b/day3/test_input
@@ -1,4 +1,4 @@
+818181911112111
 987654321111111
 811111111111119
-234234234234278
-818181911112111
\ No newline at end of file
+234234234234278
\ No newline at end of file