finished solution

day05/solution01.rb

@@ -0,0 +1,34 @@
+#!/bin/env ruby
+
+ids = []
+File.readlines('./input').each do |line|
+    line.strip!
+    row = [0, 127]
+    col = [0, 7]
+    step = 64
+    line[..6].each_char do |char|
+        row[0] += step if char == 'B'
+        row[1] -= step if char == 'F'
+        step /= 2
+    end
+    step = 4
+    line[-3..].each_char do |char|
+        col[0] += step if char == 'R'
+        col[1] -= step if char == 'L'
+        step /= 2
+    end
+    id = (row[0] * 8) + col[0]
+    ids.push(id)
+    puts "Seat #{line} is at row #{row} and column #{col}. Seat id: #{id}"
+end
+
+puts "The highest seat ID is #{ids.max}"
+ids.sort!
+ids.each_index do |i|
+    next if i == 0
+    if ids[i] != (ids[i-1] + 1)
+        puts "My seat is #{ids[i] - 1}"
+        break
+    end
+end
+