From 4de110a51759849af88d8ba974b82f001f9cf15e Mon Sep 17 00:00:00 2001
From: Thraix <thraix@hotmail.com>
Date: Tue, 4 Aug 2026 23:13:43 +0200
Subject: [PATCH] Add solution for 2015 Day 24

---
 res/2015/day24/test_input.txt |  10 +++
 src/2015/Day24.cpp            | 128 +++++++++++++++++++++++++++++++---
 2 files changed, 127 insertions(+), 11 deletions(-)

diff --git a/res/2015/day24/test_input.txt b/res/2015/day24/test_input.txt
index e69de29..f4909b4 100644
--- a/res/2015/day24/test_input.txt
+++ b/res/2015/day24/test_input.txt
@@ -0,0 +1,10 @@
+1
+2
+3
+4
+5
+7
+8
+9
+10
+11
diff --git a/src/2015/Day24.cpp b/src/2015/Day24.cpp
index dcfa9a8..6f365df 100644
--- a/src/2015/Day24.cpp
+++ b/src/2015/Day24.cpp
@@ -2,30 +2,136 @@
 
 namespace y2015::day24
 {
-  REGISTER_DAY(2015, Day24, std::vector<int>, int);
+  REGISTER_DAY(2015, Day24, std::vector<int>, uint64_t);
 
-  REGISTER_TEST_EXAMPLE(2015, Day24, ExampleInput, 1, 0);
-  REGISTER_TEST(2015, Day24, Input, 1, 0);
-  REGISTER_TEST_EXAMPLE(2015, Day24, ExampleInput, 2, 0);
-  REGISTER_TEST(2015, Day24, Input, 2, 0);
+  REGISTER_TEST_EXAMPLE(2015, Day24, ExampleInput, 1, 99);
+  REGISTER_TEST(2015, Day24, Input, 1, 11266889531);
+  REGISTER_TEST_EXAMPLE(2015, Day24, ExampleInput, 2, 44);
+  REGISTER_TEST(2015, Day24, Input, 2, 77387711);
 
   READ_INPUT(input)
   {
-    std::vector<int> vec;
-    std::string str;
-    while (getline(input, str))
+    return Input::ReadInts(input);
+  }
+
+  void GetAllSumCombinations(std::vector<int>& listLeft,
+                             std::vector<int>& currentList,
+                             std::vector<std::vector<int>>& result,
+                             int sumLeft,
+                             size_t offset)
+  {
+    if (sumLeft < 0)
+      return;
+    if (sumLeft == 0)
     {
+      result.emplace_back(currentList);
+      return;
     }
-    return vec;
+
+    for (size_t i = offset; i < listLeft.size(); i++)
+    {
+      if (listLeft[i] == 0)
+        continue;
+      if (sumLeft < listLeft[i])
+        break;
+      currentList.emplace_back(listLeft[i]);
+      int number = listLeft[i];
+      listLeft[i] = 0;
+      GetAllSumCombinations(listLeft, currentList, result, sumLeft - number, i + 1);
+      currentList.pop_back();
+      listLeft[i] = number;
+    }
+  }
+
+  std::vector<std::vector<int>> GetAllSumCombinations(std::vector<int> list, int sum, int groups)
+  {
+    std::vector<int> currentList{};
+    std::vector<std::vector<int>> result{};
+    GetAllSumCombinations(list, currentList, result, sum / groups, 0);
+    return result;
+  }
+
+  bool Overlap(const std::vector<int>& list1, const std::vector<int>& list2)
+  {
+    size_t i1 = 0;
+    size_t i2 = 0;
+    while (i1 < list1.size() && i2 < list2.size())
+    {
+      if (list1[i1] == list2[i2])
+        return true;
+
+      if (list1[i1] < list2[i2])
+        i1++;
+      else
+        i2++;
+    }
+    return false;
+  }
+
+  bool Overlap(const std::vector<int>& combination, const std::vector<const std::vector<int>*>& combinationList)
+  {
+    for (const auto& elem : combinationList)
+    {
+      if (Overlap(combination, *elem))
+        return true;
+    }
+    return false;
+  }
+
+  bool HasSolution(const std::vector<std::vector<int>>& sumCombinations,
+                   const std::vector<const std::vector<int>*>& list,
+                   size_t offset,
+                   int groupsLeft)
+  {
+    for (size_t i = offset; i < sumCombinations.size(); i++)
+    {
+      if (Overlap(sumCombinations[i], list))
+        continue;
+      if (groupsLeft == 1)
+        return true;
+
+      std::vector<const std::vector<int>*> newList = list;
+      newList.emplace_back(&sumCombinations[i]);
+      if (HasSolution(sumCombinations, newList, i + 1, groupsLeft - 1))
+        return true;
+    }
+    return false;
+  }
+
+  uint64_t Solve(const std::vector<int>& list, int groups)
+  {
+    int sum = Helper::Sum<int>(list);
+    std::vector<std::vector<int>> sumCombinations = GetAllSumCombinations(list, sum, groups);
+
+    size_t minSize = std::numeric_limits<size_t>::max();
+    for (size_t i = 0; i < sumCombinations.size(); i++)
+    {
+      minSize = std::min(minSize, sumCombinations[i].size());
+    }
+
+    uint64_t minProd = std::numeric_limits<uint64_t>::max();
+    for (size_t i = 0; i < sumCombinations.size(); i++)
+    {
+      if (sumCombinations[i].size() != minSize)
+        continue;
+      size_t product = Helper::Product<uint64_t>(sumCombinations[i]);
+      if (product >= minProd)
+        continue;
+
+      if (HasSolution(sumCombinations, {&sumCombinations[i]}, 0, groups - 1))
+        minProd = product;
+    }
+
+    return minProd;
   }
 
   OUTPUT1(input)
   {
-    return 0;
+    return Solve(input, 3);
   }
 
   OUTPUT2(input)
   {
-    return 0;
+    return Solve(input, 4);
   }
 }