aoc 2017, days 1-20

1 files changed, 118 insertions, 0 deletions

diff --git a/2017/src/day08.cpp b/2017/src/day08.cpp
new file mode 100644
index 0000000..64c1ea0
--- /dev/null
+++ b/2017/src/day08.cpp
@@ -0,0 +1,118 @@
+#include <filesystem>
+#include <fstream>
+#include <iostream>
+#include <map>
+#include <sstream>
+#include <string>
+#include <vector>
+
+using namespace std;
+
+namespace {
+
+vector<string>
+split(const string& line, char sep = ' ')
+{
+        stringstream   strm{ line };
+        vector<string> parts;
+
+        for ( string part; getline(strm, part, sep); ) {
+                parts.emplace_back(part);
+        }
+
+        return parts;
+}
+
+vector<vector<string>>
+read_file(const filesystem::path& filename)
+{
+        ifstream               file{ filename };
+        vector<vector<string>> data;
+
+        for ( string line; getline(file, line); ) {
+                auto parts = split(line);
+                data.emplace_back(parts);
+        }
+
+        return data;
+}
+
+void
+compute(const vector<vector<string>>& data, map<string, int>& memory, int& max_value)
+{
+        auto match = [](int lhs, string_view rel, int rhs) {
+                if ( rel == "==" ) {
+                        return lhs == rhs;
+                }
+                else if ( rel == "!=" ) {
+                        return lhs != rhs;
+                }
+                else if ( rel == "<" ) {
+                        return lhs < rhs;
+                }
+                else if ( rel == "<=" ) {
+                        return lhs <= rhs;
+                }
+                else if ( rel == ">" ) {
+                        return lhs > rhs;
+                }
+                else if ( rel == ">=" ) {
+                        return lhs >= rhs;
+                }
+
+                throw runtime_error("unknown relation operator: "s + string(rel));
+        };
+
+        auto execute = [&](const string& reg, string_view opcode, int value) {
+                if ( opcode == "inc" ) {
+                        memory[reg] += value;
+                }
+                else if ( opcode == "dec" ) {
+                        memory[reg] -= value;
+                }
+                else {
+                        throw runtime_error("unknown opcode: "s + string(opcode));
+                }
+        };
+
+        for ( const auto& instr: data ) {
+                const auto& reg    = instr.at(0);
+                const auto& opcode = instr.at(1);
+                const auto  value  = stoi(instr.at(2));
+                const auto  lhs    = memory[instr.at(4)];
+                const auto& rel    = instr.at(5);
+                const auto  rhs    = stoi(instr.at(6));
+
+                if ( match(lhs, rel, rhs) ) {
+                        execute(reg, opcode, value);
+                        max_value = max(max_value, memory[reg]);
+                }
+        }
+}
+
+void
+solve(const vector<vector<string>>& data)
+{
+        map<string, int> memory;
+        auto             max_value = numeric_limits<int>::min();
+
+        compute(data, memory, max_value);
+
+        auto itr = ranges::max_element(memory, [](const auto& lhs, const auto& rhs) { return lhs.second < rhs.second; });
+        cout << "Part1: " << itr->second << '\n';
+        cout << "Part2: " << max_value << '\n';
+}
+
+} // namespace
+
+int
+main()
+{
+        auto data = read_file("data/day08.txt");
+        try {
+                solve(data);
+        }
+        catch ( exception& e ) {
+                cerr << "Fehler: " << e.what() << '\n';
+        }
+}