「🎉」 init(2025): day 1

2024/day07/part1.rb

@@ -0,0 +1,60 @@
+if File.exists?("input.txt")
+  file = File.open("input.txt")
+  file_data = file.read
+  file.close
+else
+  file_data = "190: 10 19\n3267: 81 40 27\n83: 17 5\n156: 15 6\n7290: 6 8 6 15\n161011: 16 10 13\n192: 17 8 14\n21037: 9 7 18 13\n292: 11 6 16 20"
+end
+
+def eval_left_to_right(expression)
+  tokens = expression.split(/(\+|\*)/).map(&:strip)
+
+  result = tokens.shift.to_i
+  until tokens.empty?
+    operator = tokens.shift
+    operand = tokens.shift.to_i
+
+    result = result.send(operator, operand)
+  end
+
+  result
+end
+
+#puts file_data
+data_array = file_data.split("\n")
+results = []
+values = []
+
+for line in data_array do
+  res, val = line.split(":").map(&:strip)
+  res = res.to_i
+  val = val.split.map(&:to_i)
+  results.push(res)
+  values.push(val)
+end
+
+puts results.inspect
+puts values.inspect
+
+res = 0
+operations = ['+', '*']
+
+results.each_with_index do |result, index|
+  puts "\nindex: #{index} | #{result} : #{values[index]}"
+
+  combinations = operations.repeated_permutation(values[index].length - 1).to_a
+
+  combinations.each do |comb|
+    expr = values[index].zip(comb).flatten.compact.join
+    puts "#{expr} = #{eval_left_to_right(expr)}"
+
+    if eval_left_to_right(expr) == result
+      puts "#{result}"
+      res += result
+      break
+    end
+
+  end
+end
+
+puts res