Add day 2 and partial day3

src/day2/day2.rb

@@ -0,0 +1,60 @@
+Point = Struct.new(:x, :y) do
+  def +(other)
+    self.class.new(self.x + other.x, self.y + other.y) 
+  end
+end
+
+def process_input(input_string)
+  split = input_string.split
+  return split.first.to_sym, split.last.to_i
+end
+
+def step_to_point(direction, amount)
+  x = y = 0
+  case direction
+  when :forward
+    x = amount
+  when :down
+    y = amount
+  when :up
+    y = -amount
+  end
+  return Point.new(x, y)
+end
+
+position = Point.new(0, 0)
+inputs = ARGF.read.lines
+inputs.map do |input|
+  direction, amount = process_input(input)
+  point = step_to_point(direction, amount)
+  position += position + point
+end
+
+puts "Position is (#{position.x}, #{position.y})"
+puts "The product of depth and height is #{position.x * position.y}"
+
+# Aim portion
+def step_to_point_with_aim(direction, amount, aim)
+  x = y = 0
+  case direction
+  when :forward
+    x += amount
+    y += amount * aim
+  when :down
+    aim += amount
+  when :up
+    aim -= amount
+  end
+  return Point.new(x, y), aim
+end
+
+position = Point.new(0, 0)
+aim = 0
+inputs.map do |input|
+  direction, amount = process_input(input)
+  point, aim = step_to_point_with_aim(direction, amount, aim)
+  position += position + point
+end
+
+puts "Position considering aim is (#{position.x}, #{position.y})"
+puts "The product of depth and height considering aim is #{position.x * position.y}"

src/day3/day3.rb

@@ -0,0 +1,52 @@
+def process_input(input)
+  input.strip.to_i(2)
+end
+
+def find_most_common_bit(report)
+  bit_length = report.first.bit_length 
+
+  ones_count = []
+  zeros_count = []
+  report.each do |column|
+    index = 0
+    while index <= bit_length + 1 do
+      ones_count[index] ||= 0
+      zeros_count[index] ||= 0
+      case column[index] 
+        when 0 then zeros_count[index] += 1
+        when 1 then ones_count[index] += 1
+      end
+      index += 1
+    end
+  end
+  result = ones_count.zip(zeros_count)
+  puts "Result: #{result}"
+  result.map do |digit|
+    if digit.first > digit.last then 1 else 0 end
+  end
+  return result
+end
+
+def find_least_common_bit(report)
+  most_common_bit = find_most_common_bit(report)
+  least_common_bit = most_common_bit.map do |bit|
+    case bit
+      when 0 then 1
+      when 1 then 0
+    end
+  end
+  return least_common_bit
+end
+
+inputs = ARGF.read.lines
+
+puts "Report looks like: "
+report = []
+inputs.each do |input|
+  puts "  #{input}"
+  processed_input = process_input(input)
+  report << processed_input
+end
+
+puts "Gamma Rate: #{find_most_common_bit(report)}"
+puts "Epsilon Rate: #{find_least_common_bit(report)}"

src/day3/input

@@ -0,0 +1,12 @@
+00100
+11110
+10110
+10111
+10101
+01111
+00111
+11100
+10000
+11001
+00010
+01010