Mercurial > repos > other > adventofcode2023
view day12-failed.rb @ 23:f34254b67082
Add failed and almost complete Day 12 part 1
Read some discussion around solutions in other languages,
realised that recursion may work. And we can do caching.
Also includes failed map/reduce attempts.
author | IBBoard <dev@ibboard.co.uk> |
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date | Sat, 16 Dec 2023 20:04:27 +0000 |
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#! /usr/bin/env ruby if ARGV.length != 1 abort("Incorrect arguments - needs input file") elsif not File.exist? (ARGV[0]) abort("File #{ARGV[0]} did not exist") end file = ARGV[0] RowData = Struct.new(:symbols, :counts) CandidateCollector = Struct.new(:completed, :pending) def find_earliest_positions(symbols, counts) # We need to skip items (to separate each object) but I don't know enough Ruby to # do that in a map/reduce/etc (if it's even possible), so just use classic iteration char_pos = 0 count_pos = 0 match_start = 0 earliest_matches = [] # puts "Counts: #{counts}" while char_pos < symbols.length # FIXME: Doesn't take account of pre-existing fixed blocks if there are enough question marks if symbols[char_pos] != "." if (char_pos - match_start + 1) == counts[count_pos] if symbols[char_pos+1] != "#" earliest_matches << match_start # puts "At #{char_pos} found #{counts[count_pos]} chars from #{match_start} -- #{earliest_matches}" # We have to allow one space as well as moving on match_start = char_pos + 2 count_pos += 1 else # We can't have found it because there's not a space! Shuffle along one. match_start += 1 end # Else we're still in the middle of it end elsif match_start < char_pos match_start = char_pos + 1 end char_pos += 1 end earliest_matches end data = File.open(file, "r").each_line(chomp: true).map do |line| symbols, counts_str = line.split(" ") counts = counts_str.split(",").map(&:to_i) # There's nothing like Python's strip to strip all matching characters # So use a regex to just get the characters that could be items candidate_symbols = /\.*?([^.].+[^.]).*?/.match(symbols)[1] puts candidate_symbols earliest_matches = find_earliest_positions(candidate_symbols, counts) latest_matches = find_earliest_positions(candidate_symbols.reverse, counts.reverse).reverse.zip(counts).map {|pos, count| candidate_symbols.length - pos - count} puts "#{earliest_matches} to #{latest_matches}" # Assume lines are less than 100 chars and put a fake end in so we reduce to the end earliest_matches << 100 latest_matches << 100 ranges = earliest_matches.zip(latest_matches).map {|vals| Range.new(*vals)} sum = ranges.zip(counts).reduce([1, [(-1..-1), 0]]) do |accum, next_range_parts| size, cur_range_parts = accum cur_range, cur_count = cur_range_parts next_range, next_count = next_range_parts if cur_range.max >= next_range.min # Overlap - do combinations remaining_next_range = next_range.max - cur_range.max - cur_count triangular = ((next_range.size * (next_range.size + 1)) / 2) puts "#{remaining_next_range} => #{triangular}" new_range = (cur_range.max + cur_count + 1)..next_range.end [size * triangular, [new_range, next_count]] else puts "#{cur_range} => #{cur_range.size}" [size * cur_range.size, next_range_parts] end end puts sum[0] puts =begin # Aborted attempt trying to use regex to start to find positions for us count_parts = counts.split(",").map {|count| "([#\?]{#{count.to_i}})"} counts_re = /[.?]*#{count_parts.join("[.?]+")}[.?]*/ puts symbols match = symbols.match(counts_re) captures = match.captures puts "#{captures}" found = captures.map {|v| v.each_char.all?{|c| c == "#"}} puts "#{found}" puts captures.each.with_index(1).map {|v, i| "#{v} at #{match.offset(i)}"} =end RowData.new(symbols, counts) end puts data # Rest of algorithm here