From b4c9a987745cb784ad75373029a77d4ab6429c19 Mon Sep 17 00:00:00 2001 From: Nat Lasseter Date: Fri, 7 Dec 2018 11:25:40 +0000 Subject: [day07] Done --- day07/part1 | 30 ++++++++++++++++++++++++++++++ 1 file changed, 30 insertions(+) create mode 100755 day07/part1 (limited to 'day07/part1') diff --git a/day07/part1 b/day07/part1 new file mode 100755 index 0000000..bd92758 --- /dev/null +++ b/day07/part1 @@ -0,0 +1,30 @@ +#!/usr/bin/env ruby + +input = $stdin.readlines.map do |i| + i =~ /Step ([A-Z]) must be finished before step ([A-Z]) can begin./ + [$2, $1] +end + +steps = input.flatten.uniq.sort +prereqs = {} + +steps.each do |s| + prereqs[s] = [] +end + +input.each do |i| + prereqs[i.first] << i.last +end + +order = [] + +until prereqs.empty? do + next_step = prereqs.select { |k,v| v.empty? }.keys.sort.first + order << next_step + prereqs.delete(next_step) + prereqs.each_key do |k| + prereqs[k].delete(next_step) + end +end + +puts order.join -- cgit v1.2.3