34 lines
850 B
Tcl
34 lines
850 B
Tcl
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#!/usr/bin/env tclsh
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source ../prelude.tcl
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proc read_input {input} {
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set dirs [split [gets $input] ""] ;# LR...
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if {[gets $input] ne ""} { error "invalid input" }
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set graph {}
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while {[gets $input line] >= 0} {
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must_regexp {^([A-Z]+) = \(([A-Z]+), ([A-Z]+)\)$} $line _ node left right
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lappend graph [list $node $left $right]
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}
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return [list $dirs $graph]
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}
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proc solve {input} {
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lassign [read_input $input] dirs graph
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foreach x $graph {
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lassign $x node l r
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set G($node) [list $l $r]
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}
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puts [array get G]
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set node AAA
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set steps 0
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while {$node ne "ZZZ"} {
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set d [lindex $dirs [expr {$steps % [llength $dirs]}]]
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set node [lindex $G($node) [expr {($d eq "L") ? 0 : 1}]]
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puts "$d -> $node"
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incr steps
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}
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puts "$steps"
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}
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solve stdin
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