2018-15 checkpoint

2017/19.cpp

@@ -0,0 +1,79 @@
+#include <cstdint>
+#include <cctype>
+#include <iostream>
+#include <sstream>
+#include <string>
+#include <tuple>
+#include <vector>
+
+#include <doctest.h>
+
+#include <aocpp/Startup.hpp>
+#include <aocpp/Grid.hpp>
+#include <aocpp/Coord.hpp>
+
+using namespace aocpp;
+
+namespace {
+
+auto Drive(Grid const& grid) -> std::pair<std::string, int>
+{
+  std::string path;
+  int steps = 0;
+
+  Coord here {};
+  Coord dir {0,1};
+
+  // Find starting column
+  for (std::size_t i = 0; i < grid.rows[0].size(); i++) {
+    if (grid.rows[0][i] != ' ') {
+      here.x = i;
+      break;
+    }
+  }
+
+  for(;;) {
+    char c = grid[here];
+    if (c == '+') {
+      if (grid[here + CW(dir)] != ' ') {
+        dir = CW(dir);
+      } else if (grid[here + CCW(dir)] != ' ') {
+        dir = CCW(dir);
+      }
+    } else if (c == ' ') {
+      break;
+    } else if (std::isalpha(c)) {
+      path += c;
+    }
+    steps++;
+    here += dir;
+  }
+
+  return {path, steps};
+}
+
+} // namespace
+
+TEST_SUITE("2017-19 examples") {
+  TEST_CASE("example") {
+    std::istringstream in {
+      "     |          \n"
+      "     |  +--+    \n"
+      "     A  |  C    \n"
+      " F---|--|-E---+ \n"
+      "     |  |  |  D \n"
+      "     +B-+  +--+ \n"
+      "                \n"
+    };
+    auto [p1,p2] = Drive(Grid::Parse(in));
+    CHECK(p1 == "ABCDEF");
+    CHECK(p2 == 38);
+  }
+}
+
+auto main(int argc, char** argv) -> int {
+  auto input = Grid::Parse(*aocpp::Startup(argc, argv));
+  auto [part1, part2] = Drive(input);
+  std::cout << "Part 1: " << part1 << std::endl;
+  std::cout << "Part 2: " << part2 << std::endl;
+}

2017/CMakeLists.txt

@@ -24,3 +24,6 @@ target_link_libraries(2017_17 aocpp)
 
 add_executable(2017_18 18.cpp)
 target_link_libraries(2017_18 aocpp)
+
+add_executable(2017_19 19.cpp)
+target_link_libraries(2017_19 aocpp)