2016 day3

1 files changed, 38 insertions, 8 deletions

diff --git a/src/2016/day3/aoc.cpp b/src/2016/day3/aoc.cpp
index bd10b4f..41267b0 100644
--- a/src/2016/day3/aoc.cpp
+++ b/src/2016/day3/aoc.cpp
@@ -11,9 +11,8 @@ void get_number(const char** pp, int* d) {
   *pp = p;
 }
 
-bool is_triangle(line_view lv) {
+void get_sides(line_view lv, int is[]) {
   const char* p = lv.line;
-  int is[3] = {0};
   size_t i{0};
   while (p < lv.line + lv.length) {
     if (*p >= '0' && *p <= '9') {
@@ -21,19 +20,50 @@ bool is_triangle(line_view lv) {
     }
     p++;
   }
+}
+
+int is_triangle(int is[]) {
   auto b1 = is[0] + is[1] > is[2];
   auto b2 = is[0] + is[2] > is[1];
   auto b3 = is[1] + is[2] > is[0];
-  return b1 && b2 && b3;
+  return int(b1 && b2 && b3);
 }
 
-int day3(line_view file) {
-  int total{0};
-  per_line(file, [&total](line_view lv) {
-    total += int(is_triangle(lv));
+int has_triangle(int is[]) {
+  auto b1 = is[0] + is[3] > is[6];
+  auto b2 = is[0] + is[6] > is[3];
+  auto b3 = is[3] + is[6] > is[0];
+
+  auto b4 = is[1] + is[4] > is[7];
+  auto b5 = is[1] + is[7] > is[4];
+  auto b6 = is[4] + is[7] > is[1];
+
+  auto b7 = is[2] + is[5] > is[8];
+  auto b8 = is[2] + is[8] > is[5];
+  auto b9 = is[5] + is[8] > is[2];
+
+  return int(b1 && b2 && b3) + int(b4 && b5 && b6) + int(b7 && b8 && b9);
+}
+
+std::pair<int, int> day3(line_view file) {
+  int t0{0};
+  int t1{0};
+  size_t i{0};
+  const char* p = file.line;
+  per_line(file, [&t0, &t1, &i, &p](line_view lv) {
+    i++;
+    if (i % 3 == 0) {
+      int xs[9] = {0};
+      get_sides(line_view{p, lv.line + lv.length}, xs);
+      t1 += has_triangle(xs);
+      p = lv.line + lv.length + 1;
+    }
+    int is[3] = {0};
+    get_sides(lv, is);
+    t0 += is_triangle(is);
     return true;
   });
-  return total;
+  return {t0, t1};
 }
 
 } // namespace aoc2016