Mercurial > repos > other > adventofcode2023
comparison 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> |
---|---|
date | Sat, 16 Dec 2023 20:04:27 +0000 |
parents | |
children |
comparison
equal
deleted
inserted
replaced
22:ad73a2ff3d06 | 23:f34254b67082 |
---|---|
1 #! /usr/bin/env ruby | |
2 | |
3 if ARGV.length != 1 | |
4 abort("Incorrect arguments - needs input file") | |
5 elsif not File.exist? (ARGV[0]) | |
6 abort("File #{ARGV[0]} did not exist") | |
7 end | |
8 | |
9 file = ARGV[0] | |
10 | |
11 RowData = Struct.new(:symbols, :counts) | |
12 CandidateCollector = Struct.new(:completed, :pending) | |
13 | |
14 def find_earliest_positions(symbols, counts) | |
15 # We need to skip items (to separate each object) but I don't know enough Ruby to | |
16 # do that in a map/reduce/etc (if it's even possible), so just use classic iteration | |
17 char_pos = 0 | |
18 count_pos = 0 | |
19 match_start = 0 | |
20 earliest_matches = [] | |
21 # puts "Counts: #{counts}" | |
22 while char_pos < symbols.length | |
23 # FIXME: Doesn't take account of pre-existing fixed blocks if there are enough question marks | |
24 if symbols[char_pos] != "." | |
25 if (char_pos - match_start + 1) == counts[count_pos] | |
26 if symbols[char_pos+1] != "#" | |
27 earliest_matches << match_start | |
28 # puts "At #{char_pos} found #{counts[count_pos]} chars from #{match_start} -- #{earliest_matches}" | |
29 # We have to allow one space as well as moving on | |
30 match_start = char_pos + 2 | |
31 count_pos += 1 | |
32 else | |
33 # We can't have found it because there's not a space! Shuffle along one. | |
34 match_start += 1 | |
35 end | |
36 # Else we're still in the middle of it | |
37 end | |
38 elsif match_start < char_pos | |
39 match_start = char_pos + 1 | |
40 end | |
41 char_pos += 1 | |
42 end | |
43 earliest_matches | |
44 end | |
45 | |
46 data = File.open(file, "r").each_line(chomp: true).map do |line| | |
47 symbols, counts_str = line.split(" ") | |
48 counts = counts_str.split(",").map(&:to_i) | |
49 | |
50 # There's nothing like Python's strip to strip all matching characters | |
51 # So use a regex to just get the characters that could be items | |
52 candidate_symbols = /\.*?([^.].+[^.]).*?/.match(symbols)[1] | |
53 puts candidate_symbols | |
54 earliest_matches = find_earliest_positions(candidate_symbols, counts) | |
55 latest_matches = find_earliest_positions(candidate_symbols.reverse, counts.reverse).reverse.zip(counts).map {|pos, count| candidate_symbols.length - pos - count} | |
56 puts "#{earliest_matches} to #{latest_matches}" | |
57 # Assume lines are less than 100 chars and put a fake end in so we reduce to the end | |
58 earliest_matches << 100 | |
59 latest_matches << 100 | |
60 ranges = earliest_matches.zip(latest_matches).map {|vals| Range.new(*vals)} | |
61 sum = ranges.zip(counts).reduce([1, [(-1..-1), 0]]) do |accum, next_range_parts| | |
62 size, cur_range_parts = accum | |
63 cur_range, cur_count = cur_range_parts | |
64 next_range, next_count = next_range_parts | |
65 | |
66 if cur_range.max >= next_range.min | |
67 # Overlap - do combinations | |
68 remaining_next_range = next_range.max - cur_range.max - cur_count | |
69 triangular = ((next_range.size * (next_range.size + 1)) / 2) | |
70 puts "#{remaining_next_range} => #{triangular}" | |
71 new_range = (cur_range.max + cur_count + 1)..next_range.end | |
72 [size * triangular, [new_range, next_count]] | |
73 else | |
74 puts "#{cur_range} => #{cur_range.size}" | |
75 [size * cur_range.size, next_range_parts] | |
76 end | |
77 end | |
78 puts sum[0] | |
79 puts | |
80 | |
81 =begin | |
82 # Aborted attempt trying to use regex to start to find positions for us | |
83 count_parts = counts.split(",").map {|count| "([#\?]{#{count.to_i}})"} | |
84 counts_re = /[.?]*#{count_parts.join("[.?]+")}[.?]*/ | |
85 puts symbols | |
86 match = symbols.match(counts_re) | |
87 captures = match.captures | |
88 puts "#{captures}" | |
89 found = captures.map {|v| v.each_char.all?{|c| c == "#"}} | |
90 puts "#{found}" | |
91 puts captures.each.with_index(1).map {|v, i| "#{v} at #{match.offset(i)}"} | |
92 =end | |
93 RowData.new(symbols, counts) | |
94 end | |
95 puts data | |
96 # Rest of algorithm here |