From 5987591a2a8cc85f204af9a20517d37b7563236c Mon Sep 17 00:00:00 2001
From: Bill Rossi <bassguitarbill@gmail.com>
Date: Thu, 12 Dec 2024 03:38:38 -0500
Subject: [PATCH] c 2024 day 12 part 2

---
 c/2024/12/garden_groups.c | 93 ++++++++++++++++++++++++++++++++++++---
 1 file changed, 88 insertions(+), 5 deletions(-)

diff --git a/c/2024/12/garden_groups.c b/c/2024/12/garden_groups.c
index 7a08287..ad6df97 100644
--- a/c/2024/12/garden_groups.c
+++ b/c/2024/12/garden_groups.c
@@ -45,10 +45,92 @@ int region_perimeter(Region *r) {
   return perimeter;
 }
 
+int region_inner_corner_count(Region *r) {
+  int inner_corners = 0;
+  for (int i = 0; i < r->positions_count; i++) {
+    int position = r->positions[i];
+    bool up = false, down = false, left = false, right = false;
+    bool up_left = false, down_left = false, up_right = false, down_right = false;
+
+    if (position - r->map->width - 1 >= 0 && r->map->data[position - r->map->width - 1] == r->plant - 'A' + 'a') {
+      up_left = true;
+    }
+
+    if (position - r->map->width >= 0 && r->map->data[position - r->map->width] == r->plant - 'A' + 'a') {
+      up = true;
+    }
+
+    if (position - r->map->width + 1 >= 0 && r->map->data[position - r->map->width + 1] == r->plant - 'A' + 'a') {
+      up_right = true;
+    }
+
+    if (position - 1 > 0 && r->map->data[position - 1] == r->plant - 'A' + 'a') {
+      left = true;
+    }
+
+    if (position + 1 < r->map->input_length && r->map->data[position + 1] == r->plant - 'A' + 'a') {
+      right = true;
+    }
+
+    if (position + r->map->width - 1 < r->map->input_length && r->map->data[position + r->map->width - 1] == r->plant - 'A' + 'a') {
+      down_left = true;
+    }
+
+    if (position + r->map->width < r->map->input_length && r->map->data[position + r->map->width] == r->plant - 'A' + 'a') {
+      down = true;
+    }
+
+    if (position + r->map->width + 1 < r->map->input_length && r->map->data[position + r->map->width + 1] == r->plant - 'A' + 'a') {
+      down_right = true;
+    }
+
+
+    if (up && left && !up_left) inner_corners++;
+    if (up && right && !up_right) inner_corners++;
+    if (down && left && !down_left) inner_corners++;
+    if (down && right && !down_right) inner_corners++;
+  }
+
+  return inner_corners;
+}
+
+int region_outer_corner_count(Region *r) {
+  int outer_corners = 0;
+  for (int i = 0; i < r->positions_count; i++) {
+    int position = r->positions[i];
+    int fences = 0;
+    bool top_fence = false, left_fence = false, right_fence = false, bottom_fence = false;
+    if (position - r->map->width < 0 || r->map->data[position - r->map->width] != r->plant - 'A' + 'a') {
+      top_fence = true;
+    }
+
+    if (position - 1 < 0 || r->map->data[position - 1] != r->plant - 'A' + 'a') {
+      left_fence = true;
+    }
+
+    if (position + 1 > r->map->input_length || r->map->data[position + 1] != r->plant - 'A' + 'a') {
+      right_fence = true;
+    }
+    if (position + r->map->width > r->map->input_length || r->map->data[position + r->map->width] != r->plant - 'A' + 'a') {
+      bottom_fence = true;
+    }
+
+    if (top_fence && left_fence) outer_corners++;
+    if (bottom_fence && left_fence) outer_corners++;
+    if (top_fence && right_fence) outer_corners++;
+    if (bottom_fence && right_fence) outer_corners++;
+  }
+  return outer_corners;
+}
+
 int region_price(Region *r) {
-  int rp = region_perimeter(r);
-  int price = rp * r->positions_count;
-  return price;
+  return region_perimeter(r) * r->positions_count;
+}
+
+int region_price_2(Region *r) {
+  int roc = region_outer_corner_count(r);
+  int ric = region_inner_corner_count(r);
+  return (roc + ric) * r->positions_count;
 }
 
 int main() {
@@ -121,14 +203,15 @@ int main() {
   }
 
   int cost = 0;
+  int cost_2 = 0;
 
   for (int i = 0; i < m.regions_count; i++) {
     cost += region_price(&m.regions[i]);
-    // printf("%c: %d\n", m.regions[i].plant, m.regions[i].positions_count);
+    cost_2 += region_price_2(&m.regions[i]);
   }
 
   printf("Part 1: %d\n", cost);
-  // printf("Part 2: %lld\n", big_stone_count_sum);
+  printf("Part 2: %lld\n", cost_2);
   
   aoc_free();
   return 0;