Initial commit

2015/puzzle-03-01.cc

@@ -0,0 +1,55 @@
+#include <algorithm>
+#include <cassert>
+#include <iostream>
+#include <set>
+#include <string>
+
+struct Pos {
+  Pos(int x, int y) : x_(x), y_(y) {}
+
+  bool operator<(Pos const &rhs) const noexcept {
+    return x_ < rhs.x_ || (x_ == rhs.x_ && y_ < rhs.y_);
+  }
+
+  bool operator==(Pos const &rhs) const noexcept {
+    return x_ == rhs.x_ && y_ == rhs.y_;
+  }
+
+  void move(char c) {
+    switch (c) {
+    case '>':
+      ++x_;
+      break;
+    case '<':
+      --x_;
+      break;
+    case '^':
+      ++y_;
+      break;
+    case 'v':
+      --y_;
+      break;
+    default:
+      std::cout << "Unrecognised character: " << c << "\n";
+      break;
+    }
+  }
+
+  int x_;
+  int y_;
+};
+
+int main(int argc, char **argv) {
+  for (std::string line; std::getline(std::cin, line);) {
+    std::set<Pos> visited;
+    Pos santa(0, 0);
+    visited.insert(santa);
+    for (auto c : line) {
+      santa.move(c);
+      visited.insert(santa);
+    }
+    std::cout << "Houses visited = " << visited.size() << "\n";
+  }
+
+  return 0;
+}