You are not using strict and warnings for starters. Next: 

my $root= <>;

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You should chomp it, otherwise $root will contain newline in the end. 
my %graph= %graph;

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Oh, really? 
$dist{$n2} = $dist{$n} + $graph{$n1}{$n2};

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And this is why you should use strict, note $dist{$n}, shouldn't it be $dist{$n1}?

In reply to Re: what is wrong with my Dijkstram algorithm? by zwon
in thread what is wrong with my Dijkstram algorithm? by Michael Z.

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