Day 5: If You Give a Seed a Fertilizer


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  • morrowind
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    6 months ago

    CRYSTAL

    finally solved part 2, and in just 1 second :)))

    Input = File.read("input.txt").lines
    
    # {source, destination}
    alias Map = Tuple(Range(Int64, Int64), Range(Int64, Int64))
    
    Maps = Array(Array(Map)).new(7)
    index = 1
    7.times do |i| 
    	a, index = get_ranges(index + 2)
    	Maps << a
    end
    
    part2
    # part1
    
    def part1()
    	seeds = Input[0].split(":")[1].split.map(&.to_i64)
    	locs = Array(Int64).new(7)
    	
    	seeds.each do |seed|
    		val = seed
    		Maps.each do |maplist|
    			maplist.each do |map|
    				if map[0].includes?(val)
    					val = map[1].begin + (val - map[0].begin)
    					break
    		end     end     end
    		locs << val
    	end
    	puts locs.min
    end
    
    def part2()
    	seeds = Input[0].split(":")[1].split.map(&.to_i64)
    	seeds = seeds.in_groups_of(2, 0).map { |a| a[0]..(a[0]+a[1]) }
    
    	found = false
    	loc = 0
    	until found 
    		val = loc
    		Maps.reverse_each do |maplist|
    			maplist.each do |map|
    				if map[1].includes?(val)
    					val = map[0].begin + (val - map[1].begin)
    					break
    		end     end     end
    
    		seeds.each { |seedrange| break if found = seedrange.includes?(val) }
    		loc += 1
    	end
    	puts loc - 1
    end
    
    def get_ranges(index : Int) : {Array(Map), Int32}
    	line = Input[index]
    	ranges = [] of Map
    	until line == ""
    		a, b, l = line.split.map(&.to_i64)
    		ranges << {b...(b+l), a...(a+l)}
    		
    		index += 1
    		break if index == Input.size
    		line = Input[index]
    	end
    	{ranges, index}
    end