1 files changed, 93 insertions, 0 deletions

diff --git a/2015/src/day03.cpp b/2015/src/day03.cpp
new file mode 100644
index 0000000..e81da90
--- /dev/null
+++ b/2015/src/day03.cpp
@@ -0,0 +1,93 @@
+#include <fstream>
+#include <iostream>
+#include <set>
+#include <string>
+
+using namespace std;
+
+auto
+read_file(string_view filename)
+{
+        fstream input{ filename };
+        return string{ istreambuf_iterator<char>{ input }, {} };
+}
+
+void
+part1(string_view directions)
+{
+        set<tuple<int, int>> positions{};
+        int                  xpos = 0;
+        int                  ypos = 0;
+
+        positions.emplace(xpos, ypos);
+        for ( const auto direction: directions ) {
+                switch ( direction ) {
+                case '^':
+                        --ypos;
+                        break;
+                case 'v':
+                        ++ypos;
+                        break;
+                case '<':
+                        --xpos;
+                        break;
+                case '>':
+                        ++xpos;
+                        break;
+                default:
+                        break;
+                }
+                positions.emplace(xpos, ypos);
+        }
+        cout << positions.size() << endl;
+}
+
+void
+part2(string_view directions)
+{
+        set<tuple<int, int>> positions{};
+
+        for ( string_view::size_type start = 0; start != 2; ++start ) {
+                int xpos = 0;
+                int ypos = 0;
+
+                positions.emplace(xpos, ypos);
+
+                for ( string_view::size_type idx = start; idx < directions.length(); idx += 2 ) {
+                        const auto direction = directions[idx];
+
+                        switch ( direction ) {
+                        case '^':
+                                --ypos;
+                                break;
+                        case 'v':
+                                ++ypos;
+                                break;
+                        case '<':
+                                --xpos;
+                                break;
+                        case '>':
+                                ++xpos;
+                                break;
+                        default:
+                                break;
+                        }
+                        positions.emplace(xpos, ypos);
+                }
+        }
+        cout << positions.size() << endl;
+}
+
+int
+main()
+{
+        auto directions = read_file("data/day03.txt");
+        // part1(">");
+        // part1("^>v<");
+        // part1("^v^v^v^v^v");
+        part1(directions);
+        // part2("^v");
+        // part2("^>v<");
+        // part2("^v^v^v^v^v");
+        part2(directions);
+}