Finding a Most Likely Common Ancestor (Perl 6)

ancestor.pl

# solution to http://rosalind.info/problems/cons/
use v6;
my @dna = <
    ATCCAGCT
    GGGCAACT
    ATGGATCT
    AAGCAACC
    TTGGAACT
    ATGCCATT
    ATGGCACT
>;

my $n = @dna[0].chars;
my %char_to_idx = <A C G T> Z=> 0..*;
my @m = [0 xx $n] xx 4;

for ^$n X @dna -> $i, $s {
    @m[%char_to_idx{$s.substr($i, 1)}][$i]++;
}
for ^$n -> $idx {
    print <A C G T>[@m.pairs.map({; .key => .value.[$idx] }).max(*.value).key];
}
print "\n";

for <A C G T> {
    say join ' ', "$_:", @m[%char_to_idx{$_}].list;
}