aoc 2018, days 1-11

1 files changed, 88 insertions, 0 deletions

diff --git a/2018/src/day08.cpp b/2018/src/day08.cpp
new file mode 100644
index 0000000..9c2a093
--- /dev/null
+++ b/2018/src/day08.cpp
@@ -0,0 +1,88 @@
+#include <filesystem>
+#include <fstream>
+#include <iostream>
+#include <vector>
+
+using namespace std;
+
+namespace {
+
+vector<int>
+read_file(const filesystem::path& filename)
+{
+        ifstream    file{ filename };
+        vector<int> data;
+
+        for ( int number{}; file >> number; ) {
+                data.emplace_back(number);
+        }
+
+        return data;
+}
+
+void
+part1(const vector<int>& data)
+{
+        size_t idx = 0;
+        int    sum = 0;
+
+        function<void()> func = [&] {
+                auto count_child = data.at(idx++);
+                auto count_meta  = data.at(idx++);
+
+                while ( count_child-- > 0 ) {
+                        func();
+                }
+
+                while ( count_meta-- > 0 ) {
+                        sum += data.at(idx++);
+                }
+        };
+
+        func();
+
+        cout << "Part 1: " << sum << '\n';
+}
+
+void
+part2(const vector<int>& data)
+{
+        size_t idx = 0;
+
+        function<int()> func = [&] {
+                const auto count_child = data.at(idx++);
+                const auto count_meta  = data.at(idx++);
+
+                vector<int> child_values;
+                for ( int i = 0; i != count_child; ++i ) {
+                        child_values.emplace_back(func());
+                }
+
+                int value = 0;
+                for ( int i = 0; i != count_meta; ++i ) {
+                        auto meta = data.at(idx++);
+                        if ( count_child == 0 ) {
+                                value += meta;
+                        }
+                        else {
+                                meta--;
+                                if ( meta >= 0 && meta < count_child ) {
+                                        value += child_values[static_cast<size_t>(meta)];
+                                }
+                        }
+                }
+                return value;
+        };
+
+        cout << "Part 2: " << func() << '\n';
+}
+
+} // namespace
+
+int
+main()
+{
+        auto data = read_file("data/day08.txt");
+        part1(data);
+        part2(data);
+}