40 lines
899 B
Tcl
40 lines
899 B
Tcl
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proc dijkstra {graph origin} {
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# Initialize
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dict for {vertex distmap} $graph {
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dict set dist $vertex Inf
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dict set path $vertex {}
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}
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dict set dist $origin 0
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dict set path $origin [list $origin]
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while {[dict size $graph]} {
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# Find unhandled node with least weight
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set d Inf
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dict for {uu -} $graph {
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if {$d > [set dd [dict get $dist $uu]]} {
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set u $uu
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set d $dd
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}
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}
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# No such node; graph must be disconnected
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if {$d == Inf} break
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# Update the weights for nodes\
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lead to by the node we've picked
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dict for {v dd} [dict get $graph $u] {
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if {[dict exists $graph $v]} {
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set alt [expr {$d + $dd}]
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if {$alt < [dict get $dist $v]} {
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dict set dist $v $alt
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dict set path $v [list {*}[dict get $path $u] $v]
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}
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}
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}
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# Remove chosen node from graph still to be handled
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dict unset graph $u
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}
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return [list $dist $path]
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}
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