Add Job Sequencing in Ruby

archive/r/ruby/job-sequencing.rb

@@ -0,0 +1,53 @@
+# frozen_string_literal: true
+
+USAGE = "Usage: please provide a list of profits and a list of deadlines"
+
+def usage!
+  warn USAGE
+  exit 1
+end
+
+def parse_list(str)
+  str.split(",").map { Integer(it.strip) }
+rescue ArgumentError, NoMethodError
+  usage!
+end
+
+def find(parent, x)
+  while parent[x] != x
+    parent[x] = parent[parent[x]]
+    x = parent[x]
+  end
+  x
+end
+
+def schedule(profits, deadlines)
+  jobs = profits.zip(deadlines)
+  max_d = deadlines.max
+
+  parent = (0..max_d).to_a
+
+  total = 0
+
+  jobs.sort_by { -it[0] }.each do |profit, d|
+    slot = find(parent, [d, max_d].min)
+
+    next if slot == 0
+
+    parent[slot] = slot - 1
+    total += profit
+  end
+
+  total
+end
+
+profits_str, deadlines_str = ARGV
+usage! if profits_str.nil? || deadlines_str.nil? ||
+  profits_str.strip.empty? || deadlines_str.strip.empty?
+
+profits = parse_list(profits_str)
+deadlines = parse_list(deadlines_str)
+
+usage! if profits.size != deadlines.size
+
+puts schedule(profits, deadlines)