2024 D2P1

2024/aoc.cpp

@@ -2,7 +2,7 @@
 
 #include "aoc.hpp"
 #include "day1.hpp"
-
+#include "day2.hpp"
 
 int main(int argc, char** argv)
 {

2024/aoc.hpp

@@ -86,12 +86,24 @@ public:
     /// Access tokens for a given line (1-based)
     const std::vector<FileFragment>& TokensForLine(int line) const
     {
-        if (line < 1 || line > static_cast<int>(_tokens.size()))
+        if (line < 0 || line > static_cast<int>(_tokens.size()))
         {
             static const std::vector<FileFragment> empty;
             return empty;
         }
-        return _tokens[line - 1];
+        return _tokens[line];
+    }
+
+    // Access a chunk of tokens for a given line
+    // E.g. Iterate [1,2], [2,3], [3,4]
+    std::vector<std::vector<FileFragment>> ChunkView(int line, size_t n, size_t gap) {
+        std::vector<FileFragment> v = _tokens[line];
+        std::vector<std::vector<FileFragment>> chunks;
+        for (size_t i = 0; i < v.size() - 1; i += gap) {
+            chunks.emplace_back(v.begin() + i,
+                                v.begin() + std::min(v.size(), i + n));
+        }
+        return chunks;
     }
 
     /// Iterate through all lines and their tokens

2024/day2.hpp

@@ -0,0 +1,58 @@
+#include "aoc.hpp"
+
+class Day02 : public AOCDay
+{
+public:
+    Day02() {}
+    ~Day02() {}
+    int Day() override {return 2;}
+
+    int PartOne(File& f) override
+    {
+        f.SplitBy(" ");
+
+        int result_bad = 0;
+
+        for (int i = 0; i < f.Lines().size(); i++)
+        {
+            bool lastDirection;
+            bool first = true;
+            for (const auto& tokenPair : f.ChunkView(i, 2, 1))
+            {
+                int token = std::atoi(tokenPair[0].Data.c_str());
+                int nextToken = std::atoi(tokenPair[1].Data.c_str());
+
+                int diff = token - nextToken;
+                bool direction = diff > 0;
+
+                if (first)
+                {
+                    lastDirection = direction;
+                    first = false;
+                }
+
+                if (std::abs(diff) > 3
+                 || token == nextToken
+                 || direction != lastDirection)
+                {
+                    result_bad++;
+                    break;
+                }
+
+                lastDirection = direction;
+                first = false;
+            }
+        }
+
+        int result = f.Lines().size() - result_bad;
+
+        return result;
+    }
+
+    int PartTwo(File&) override
+    {
+    }
+};
+
+ADD_AOC_DAY(Day02);
+