1 files changed, 14 insertions, 47 deletions

diff --git a/src/2019/day10/aoc.cpp b/src/2019/day10/aoc.cpp
index 60de3ea..2104343 100644
--- a/src/2019/day10/aoc.cpp
+++ b/src/2019/day10/aoc.cpp
@@ -1,6 +1,7 @@
 #include "aoc.h"
 #include <algorithm>
 #include <vector>
+#include <math.h>
 
 namespace aoc2019 {
 
@@ -10,47 +11,20 @@ struct posd {
   int count = 0;
 };
 
-enum dim {
-  xe0yl0,
-  xg0yl0,
-  xg0ye0,
-  xg0yg0,
-  xe0yg0,
-  xl0yg0,
-  xl0ye0,
-  xl0yl0
-};
-
-dim dimention(belt::distance d) {
-  if (d.dx == 0 && d.dy < 0) return xe0yl0;
-  if (d.dx > 0 && d.dy < 0) return xg0yl0;
-  if (d.dx > 0 && d.dy == 0) return xg0ye0;
-  if (d.dx > 0 && d.dy > 0) return xg0yg0;
-  if (d.dx == 0 && d.dy > 0) return xe0yg0;
-  if (d.dx < 0 && d.dy > 0) return xl0yg0;
-  if (d.dx < 0 && d.dy == 0) return xl0ye0;
-  return xl0yl0;
-}
-
-bool dimcmp(dim m, belt::distance d1, belt::distance d2) {
-  int x1 = std::abs(d1.dx);
-  int y1 = std::abs(d1.dy);
-  int x2 = std::abs(d2.dx);
-  int y2 = std::abs(d2.dy);
-
-  switch (m) {
-    case xe0yl0: return y1 < y2;
-    case xg0yl0: return y1 > y2 ? true : y1 < y2 ? false : x1 < x2;
-    case xg0ye0: return x1 < x2;
-    case xg0yg0: return y1 < y2 ? true : y1 > y2 ? false : x1 < x2;
-    case xe0yg0: return y1 < y2;
-    case xl0yg0: return y1 > y2 ? true : y1 < y2 ? false : x1 < x2;
-    case xl0ye0: return x1 < x2;
-    case xl0yl0: return y1 < y2 ? true : y1 > y2 ? false : x1 < x2;
+float angle(int x, int y) {
+  auto a = std::atan2(y, x);
+  auto r = a * 180 / M_PI;
+  if (r > 360) {
+    r -= 360;
   }
-  return false;
+  if (r < 0) {
+    r += 360;
+  }
+  r += 90;
+  return r >= 360 ? r - 360 : r;
 }
 
+
 belt::pos vaporize(belt b, belt::pos& m, std::vector<posd>& ps, int* count) {
   belt bx = b;
   for (auto& dp : ps) {
@@ -58,7 +32,7 @@ belt::pos vaporize(belt b, belt::pos& m, std::vector<posd>& ps, int* count) {
       dp.count = 1;
       b.get(dp.p) = '.';
       *count += 1;
-      printf("%d asteroid to be vaporized is at (%d, %d)\n", *count, dp.p.x, dp.p.y);
+      // printf("%d asteroid to be vaporized is at (%d, %d)\n", *count, dp.p.x, dp.p.y);
       if (*count == 200) {
         return dp.p;
       }
@@ -98,14 +72,7 @@ std::pair<int, int> day10(line_view file) {
   }
 
   std::sort(ps.begin(), ps.end(), [](const posd& d1, const posd& d2) {
-      dim m1 = dimention(d1.d);
-      dim m2 = dimention(d2.d);
-      if (m1 == m2) {
-        return dimcmp(m1, d1.d, d2.d);
-      }
-      else {
-        return (int) m1 < (int) m2;
-      }
+      return angle(d1.d.dx, d1.d.dy) < angle(d2.d.dx, d2.d.dy);
   });
 
   int count{0};