application/octet-stream
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1.74 KB
•
44 lines
#!/usr/bin/env nujel
[def cave-map @[]]
[def big-caves @[]]
[defun big-cave? [α] [big-caves α]]
[defun add-connections [line]
[def parts [map str->sym [split line "-"]]]
[tree/set! cave-map [car parts] [cons [cadr parts] [tree/get cave-map [car parts]]]]
[tree/set! cave-map [cadr parts] [cons [car parts] [tree/get cave-map [cadr parts]]]]
[tree/set! big-caves [car parts] [< [char-at [sym->str [car parts]] 0] #\a]]
[tree/set! big-caves [cadr parts] [< [char-at [sym->str [cadr parts]] 0] #\a]]
]
[def connections [for-each add-connections [split [file/read "day12.input"] "\n"]]]
[def valid-routes 0]
[defun calc-routes [position s twice]
[if [== position 'start]
[++ valid-routes]
[when-not [and [== position 'end]
[> [tree/get s 'end] 0]]
[def routes [cave-map position]]
[when-not [big-cave? position]
[when [> [tree/get s position] 0]
[if twice
[throw [list :return]]
[set! twice #t]]]
[set! s [tree/dup s]]
[tree/++ s position]
]
[while routes
[try [\ [ε] [when [!= [car ε] :return] [throw ε]]]
[calc-routes [car routes] s twice]]
[cdr! routes]]]]
]
[calc-routes 'end @[] #t]
[when [!= valid-routes 4411]
[throw [list :wrong-result "Wrong result" valid-routes]]]
[set! valid-routes 0]
[calc-routes 'end @[] #f]
[when [!= valid-routes 136767]
[throw [list :wrong-result "Wrong result" valid-routes]]]
