1 files changed, 151 insertions, 0 deletions

diff --git a/2025/src/day06.cpp b/2025/src/day06.cpp
new file mode 100644
index 0000000..af562cd
--- /dev/null
+++ b/2025/src/day06.cpp
@@ -0,0 +1,151 @@
+#include <filesystem>
+#include <fstream>
+#include <iostream>
+#include <sstream>
+#include <string>
+#include <tuple>
+#include <vector>
+
+using namespace std;
+
+namespace {
+
+using Grid = vector<vector<long>>;
+using Ops  = vector<char>;
+
+vector<string>
+read_file(const filesystem::path& filename)
+{
+        ifstream       file{ filename };
+        vector<string> lines;
+
+        for ( string line; getline(file, line); ) {
+                lines.emplace_back(line);
+        }
+
+        return lines;
+}
+
+vector<char>
+read_ops(const string& line)
+{
+        stringstream strm{ line };
+        vector<char> ops;
+        for ( char chr{}; strm >> chr; ) {
+                ops.emplace_back(chr);
+        }
+        return ops;
+}
+
+vector<long>
+read_numbers(const string& line)
+{
+        stringstream strm{ line };
+        vector<long> numbers;
+        for ( long number{}; strm >> number; ) {
+                numbers.emplace_back(number);
+        }
+        return numbers;
+}
+
+void
+part1(vector<string> lines)
+{
+        ranges::reverse(lines);
+
+        const auto ops = read_ops(lines[0]);
+
+        vector<vector<long>> grid;
+        for ( size_t i = 1; i < lines.size(); ++i ) {
+                grid.emplace_back(read_numbers(lines[i]));
+        }
+
+        long sum = 0;
+        for ( size_t col = 0; col != ops.size(); ++col ) {
+                long value = ops[col] == '*' ? 1 : 0;
+                for ( auto& row: grid ) {
+                        if ( ops[col] == '*' ) {
+                                value *= row[col];
+                        }
+                        else {
+                                value += row[col];
+                        }
+                }
+                sum += value;
+        }
+        cout << "Part 1: " << sum << '\n';
+}
+
+vector<string>
+rotateLeft90(const vector<string>& matrix)
+{
+        if ( matrix.empty() ) {
+                return {};
+        }
+
+        auto rows = matrix.size();
+        auto cols = matrix[0].size();
+
+        vector<string> res(cols, string(rows, ' '));
+
+        for ( size_t row = 0; row != rows; ++row ) {
+                for ( size_t col = 0; col != cols; ++col ) {
+                        // Position aus ursprünglicher Matrix auf neue übertragen
+                        res[cols - 1 - col][row] = matrix[row][col];
+                }
+        }
+
+        return res;
+}
+
+void
+part2(vector<string> lines)
+{
+        auto ops = read_ops(lines.back());
+        ranges::reverse(ops);
+        lines.pop_back(); // ops entfernen
+
+        // Matrix drehen
+        lines = rotateLeft90(lines);
+        lines.emplace_back("");
+
+        vector<vector<long>> grid;
+        vector<long>         curr;
+
+        // Matrix neu aufbauen
+        for ( const auto& line: lines ) {
+                if ( long number{}; sscanf(line.data(), "%ld", &number) == 1 ) {
+                        curr.emplace_back(number);
+                }
+                else {
+                        grid.emplace_back(curr);
+                        curr.clear();
+                }
+        }
+
+        // ausrechnen
+        long sum = 0;
+        for ( size_t row = 0; row != ops.size(); ++row ) {
+                long value = ops[row] == '*' ? 1 : 0;
+                for ( const auto number: grid[row] ) {
+                        if ( ops[row] == '*' ) {
+                                value *= number;
+                        }
+                        else {
+                                value += number;
+                        }
+                }
+                sum += value;
+        }
+        cout << "Part 2: " << sum << '\n';
+}
+
+} // namespace
+
+int
+main()
+{
+        const auto lines = read_file("data/day06.txt");
+        part1(lines);
+        part2(lines);
+}