From fc76349588afa69995e0f9a4ee742979c9d9edd8 Mon Sep 17 00:00:00 2001
From: Thraix <thraix@hotmail.com>
Date: Wed, 12 Aug 2026 21:00:56 +0200
Subject: [PATCH] Add solution for 2016 Day 3

---
 res/2016/day03/test_input.txt |  3 +++
 src/2016/Day03.cpp            | 43 ++++++++++++++++++++++++++---------
 src/common/lib/Input.h        | 23 +++++++++++++++++++
 3 files changed, 58 insertions(+), 11 deletions(-)

diff --git a/res/2016/day03/test_input.txt b/res/2016/day03/test_input.txt
index e69de29..dda7484 100644
--- a/res/2016/day03/test_input.txt
+++ b/res/2016/day03/test_input.txt
@@ -0,0 +1,3 @@
+5 10 25
+11 15 25
+8 25 20
diff --git a/src/2016/Day03.cpp b/src/2016/Day03.cpp
index df67cd4..e269af2 100644
--- a/src/2016/Day03.cpp
+++ b/src/2016/Day03.cpp
@@ -2,30 +2,51 @@
 
 namespace y2016::day03
 {
-  REGISTER_DAY(2016, Day03, std::vector<int>, int);
+  REGISTER_DAY(2016, Day03, Array2D<int>, int);
 
-  REGISTER_TEST_EXAMPLE(2016, Day03, ExampleInput, 1, 0);
-  REGISTER_TEST(2016, Day03, Input, 1, 0);
-  REGISTER_TEST_EXAMPLE(2016, Day03, ExampleInput, 2, 0);
-  REGISTER_TEST(2016, Day03, Input, 2, 0);
+  REGISTER_TEST_EXAMPLE(2016, Day03, ExampleInput, 1, 2);
+  REGISTER_TEST(2016, Day03, Input, 1, 983);
+  REGISTER_TEST_EXAMPLE(2016, Day03, ExampleInput, 2, 2);
+  REGISTER_TEST(2016, Day03, Input, 2, 1836);
 
   READ_INPUT(input)
   {
-    std::vector<int> vec;
-    std::string str;
-    while (getline(input, str))
+    return Input::ReadIntsAsArray2D(input);
+  }
+
+  bool IsValid(const std::array<int, 3>& triangle)
+  {
+    for (int i = 0; i < 3; i++)
     {
+      int length = triangle.at(i) + triangle.at((i + 1) % 3);
+      if (length <= triangle.at((i + 2) % 3))
+        return false;
     }
-    return vec;
+    return true;
   }
 
   OUTPUT1(input)
   {
-    return 0;
+    int count = 0;
+    for (int y = 0; y < input.height; y++)
+    {
+      if (IsValid({input.Get(0, y), input.Get(1, y), input.Get(2, y)}))
+        count++;
+    }
+    return count;
   }
 
   OUTPUT2(input)
   {
-    return 0;
+    int count = 0;
+    for (int y = 0; y < input.height; y += 3)
+    {
+      for (int x = 0; x < 3; x++)
+      {
+        if (IsValid({input.Get(x, y), input.Get(x, y + 1), input.Get(x, y + 2)}))
+          count++;
+      }
+    }
+    return count;
   }
 }
diff --git a/src/common/lib/Input.h b/src/common/lib/Input.h
index 336d853..bfe89b3 100644
--- a/src/common/lib/Input.h
+++ b/src/common/lib/Input.h
@@ -3,6 +3,7 @@
 #include <stdint.h>
 
 #include <iostream>
+#include <sstream>
 #include <string>
 
 #include "Array2D.h"
@@ -56,6 +57,28 @@ struct Input
     return Array2D<int>(width, height, data);
   }
 
+  static Array2D<int> ReadIntsAsArray2D(std::istream& input)
+  {
+    std::vector<int> data;
+    int width = 0;
+    int height = 0;
+    std::string str;
+    while (getline(input, str))
+    {
+      height++;
+      std::stringstream ss{str};
+      int i;
+      int size = 0;
+      while (ss >> i)
+      {
+        data.emplace_back(i);
+        size++;
+      }
+      width = size;
+    }
+    return Array2D<int>(width, height, data);
+  }
+
   static std::vector<int> ReadInts(std::istream& input)
   {
     return ReadInts(input, '\n');