day2 part1

1 files changed, 57 insertions, 0 deletions

diff --git a/src/2015/day2/aoc.cpp b/src/2015/day2/aoc.cpp
new file mode 100644
index 0000000..33ae6b6
--- /dev/null
+++ b/src/2015/day2/aoc.cpp
@@ -0,0 +1,57 @@
+#include "aoc.h"
+
+namespace aoc2015 {
+
+int cal_day2(const char* p1, const char* p2) {
+  int x = 0;
+  const char* p = p1;
+  while (p != p2) {
+    x = x * 10 + (*p) - '0';
+    p++;
+  }
+  return x;
+}
+
+/*
+27x2x5
+29x13x26
+*/
+box parse_day2(line_view lv) {
+  box b;
+  int* is[] = {&b.l, &b.w, &b.h};
+  const char* p1 = lv.line;
+  const char* p2 = p1;
+  const char* pe = p1 + lv.length;
+  int i = 0;
+  while (p2 != pe) {
+    if ((*p2) >= '0' && (*p2) <= '9') {
+      p2++;
+    } else {
+      *is[i++] = cal_day2(p1, p2);
+      p1 = p2 + 1;
+      p2 = p1;
+    }
+  }
+  return b;
+}
+
+inline int min_day2(box b) {
+  int x1 = b.l * b.w;
+  int x2 = b.l * b.h;
+  int x3 = b.h * b.w;
+  return std::min(std::min(x1, x2), x3);
+}
+
+inline int surface(box b) { return 2 * b.l * b.w + 2 * b.l * b.h + 2 * b.w * b.h; }
+
+int day2(line_view input) {
+  int total = 0;
+  per_line(input, [&total](line_view line) {
+    box b = parse_day2(line);
+    total += surface(b) + min_day2(b);
+    return true;
+  });
+  return total;
+}
+
+} // namespace aoc2015