2016 day1 part1

1 files changed, 35 insertions, 1 deletions

diff --git a/src/2016/day1/aoc.cpp b/src/2016/day1/aoc.cpp
index 014f893..2711d8f 100644
--- a/src/2016/day1/aoc.cpp
+++ b/src/2016/day1/aoc.cpp
@@ -1,3 +1,37 @@
 #include "aoc.h"
 
-namespace aoc2016 {}
+namespace aoc2016 {
+
+instruction parse_day1(const char** pp) {
+  instruction i;
+  const char* p = *pp;
+  i.direction = (*p++) == 'R' ? instruction::right : instruction::left;
+  i.distance = 0;
+
+  while (*p >= '0' && *p <= '9') {
+    i.distance = i.distance * 10 + *p - '0';
+    p++;
+  }
+
+  *pp = p;
+  return i;
+}
+
+int day1(line_view file) {
+  position x{position::north, 0, 0};
+  std::vector<instruction> is;
+
+  const char* p1 = file.line;
+  const char* p2 = file.line + file.length;
+  while (p1 < p2) {
+    if (*p1 == 'R' || *p1 == 'L') {
+      is.emplace_back(parse_day1(&p1));
+    } else {
+      p1++;
+    }
+  }
+  position n = x.move(is);
+  return x.blocks(n);
+}
+
+} // namespace aoc2016