From 4fb0b2c46c5ebc5fc7fce438f5c8baf8e345c9e9 Mon Sep 17 00:00:00 2001
From: Thraix <thraix@hotmail.com>
Date: Sun, 7 Dec 2025 14:20:48 +0100
Subject: [PATCH] Add solution for 2025 Day 7

---
 res/2025/day07/test_input.txt | 16 ++++++++++
 src/2025/Day07.cpp            | 60 +++++++++++++++++++++++++----------
 2 files changed, 60 insertions(+), 16 deletions(-)
 create mode 100644 res/2025/day07/test_input.txt

diff --git a/res/2025/day07/test_input.txt b/res/2025/day07/test_input.txt
new file mode 100644
index 0000000..57a2466
--- /dev/null
+++ b/res/2025/day07/test_input.txt
@@ -0,0 +1,16 @@
+.......S.......
+...............
+.......^.......
+...............
+......^.^......
+...............
+.....^.^.^.....
+...............
+....^.^...^....
+...............
+...^.^...^.^...
+...............
+..^...^.....^..
+...............
+.^.^.^.^.^...^.
+...............
diff --git a/src/2025/Day07.cpp b/src/2025/Day07.cpp
index 5b96394..0cb0446 100644
--- a/src/2025/Day07.cpp
+++ b/src/2025/Day07.cpp
@@ -2,35 +2,63 @@
 
 namespace y2025::day07
 {
-  using InputType = std::vector<int>;
-  REGISTER_DAY(2025, Day07, InputType, int);
+  using InputType = Array2D<char>;
+  REGISTER_DAY(2025, Day07, InputType, int64_t);
 
-  REGISTER_TEST_EXAMPLE(2025, Day07, ExampleInput, 1, 0);
-  REGISTER_TEST(2025, Day07, Input, 1, 0);
-  REGISTER_TEST_EXAMPLE(2025, Day07, ExampleInput, 2, 0);
-  REGISTER_TEST(2025, Day07, Input, 2, 0);
+  REGISTER_TEST_EXAMPLE(2025, Day07, ExampleInput, 1, 21);
+  REGISTER_TEST(2025, Day07, Input, 1, 1594);
+  REGISTER_TEST_EXAMPLE(2025, Day07, ExampleInput, 2, 40);
+  REGISTER_TEST(2025, Day07, Input, 2, 15650261281478);
 
   READ_INPUT(input)
   {
-    std::vector<int> vec;
-    std::string str;
-    while (std::getline(input, str))
+    return Input::ReadArray2D(input);
+  }
+
+  std::pair<int64_t, int64_t> Simulate(const Array2D<char>& grid)
+  {
+    std::pair<int64_t, int64_t> solution{0, 1};
+
+    Index2D startPos = grid.Find('S');
+
+    std::vector<int64_t> beamsRow{};
+    beamsRow.resize(grid.width);
+    beamsRow[startPos.x] = 1;
+
+    for (int y = startPos.y; y < grid.height - 1; y++)
     {
-      std::stringstream ss{str};
-      int n;
-      ss >> n;
-      vec.emplace_back(n);
+      std::vector<int64_t> nextBeamRow{};
+      nextBeamRow.resize(grid.width);
+
+      for (int x = 0; x < grid.width; x++)
+      {
+        if (beamsRow[x] == 0)
+          continue;
+
+        if (grid.Get(x, y + 1) == '^')
+        {
+          nextBeamRow[x - 1] += beamsRow[x];
+          nextBeamRow[x + 1] += beamsRow[x];
+          solution.first++;
+          solution.second += beamsRow[x];
+        }
+        else
+        {
+          nextBeamRow[x] += beamsRow[x];
+        }
+      }
+      beamsRow = std::move(nextBeamRow);
     }
-    return vec;
+    return solution;
   }
 
   OUTPUT1(input)
   {
-    return 0;
+    return Simulate(input).first;
   }
 
   OUTPUT2(input)
   {
-    return 0;
+    return Simulate(input).second;
   }
 }