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#!/usr/bin/env perl
use strict;
use warnings;
use experimental qw{ say state postderef signatures };
use List::Util qw{ sum0 };
my @examples = (
[ 2, 3, -1, 8, 4 ],
[ 1, -1, 4 ],
[ 2, 5 ],
);
# [ 1, 1, 0 ] is false, because 1 isn't 2 * 0
# [ 1, 1, 0, 0 ] is true, because 0 is 2 * 0
for my $example (@examples) {
my $output = middle_index( $example->@* );
my $input = join ', ', $example->@*;
say <<"END";
Input: \$ints = ($input)
Output: $output
END
}
sub middle_index (@array) {
my $l = -1 + scalar @array;
for my $i ( 1 .. $l ) {
my $suml = sum0 @array[ 0 .. $i - 1 ];
my $sumr = sum0 @array[ $i + 1 .. $l ];
return $i if $suml eq $sumr;
}
return -1;
}
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