1 files changed, 84 insertions, 0 deletions
diff --git a/2024/04a/run.rb b/2024/04a/run.rb
new file mode 100755
index 0000000..22118c2
--- /dev/null
+++ b/2024/04a/run.rb
@@ -0,0 +1,84 @@
+#!/usr/bin/env ruby
+
+@letters = {} 
+data = File.read("data.txt")
+data = data.split("\n")
+data = data.map(&:chars)
+data.each_with_index do |row, y|
+  row.each_with_index do |letter, x|
+    @letters[[x,y]] = letter
+  end
+end
+PREFIX = "X"
+SUFIX = %w(M A S)
+
+found = 0
+
+def find_with_vector(start_x, start_y, x, y)
+ word = (1..3).map do |iter|
+
+  @letters[[start_x + (iter * x), start_y + (iter * y)]]
+ end
+
+ true if word.to_a == SUFIX
+end
+
+potential_starts = @letters.select{|key, val| val == PREFIX } 
+potential_starts.each do |key, value| 
+
+    found+= 1 if find_with_vector(key[0], key[1], 0, 1)
+    found+= 1 if find_with_vector(key[0], key[1], 1, 0)
+
+    found+= 1 if find_with_vector(key[0], key[1], 0, -1)
+    found+= 1 if find_with_vector(key[0], key[1], -1, 0)
+
+    found+= 1 if find_with_vector(key[0], key[1], 1, 1)
+    found+= 1 if find_with_vector(key[0], key[1], -1, 1)
+    found+= 1 if find_with_vector(key[0], key[1], 1, -1)
+    found+= 1 if find_with_vector(key[0], key[1], -1, -1)
+end
+
+p found
+
+
+
+exit
+
+def find_with_vector(start_y, start_x, y, x)
+  word = (1..3).map do |offset|
+    tested_row = @data[ start_x + offset* x ]
+    return false unless tested_row
+
+    letter = tested_row[ start_y + offset * y ]
+    return unless SUFIX.include? letter
+
+    letter
+  end
+  
+  p [word, start_x, start_y, x, y] if word == SUFIX
+  true if word == SUFIX
+
+
+end
+
+found_count = 0
+@data.each_with_index do |row, y|
+  row.each_with_index do |letter, x|
+    next unless letter == "X"
+    
+    found_count += 1 if find_with_vector(x,y, 0, 1)
+    found_count += 1 if find_with_vector(x,y, 1, 0)
+
+    found_count += 1 if find_with_vector(x,y, 0, -1)
+    found_count += 1 if find_with_vector(x,y, -1, 0)
+
+    found_count += 1 if find_with_vector(x,y, 1, 1)
+    found_count += 1 if find_with_vector(x,y, -1, 1)
+    found_count += 1 if find_with_vector(x,y, 1, -1)
+    found_count += 1 if find_with_vector(x,y, -1, -1)
+
+
+  end
+end
+
+p found_count