use strict;
use warnings;
use v5.12;  




my @array = (
    [ qw/ 1 0 1 0 1 / ],
    [ qw/ 0 1 0 1 0 / ],
    [ qw/ 0 0 1 1 0 / ],
    [ qw/ 0 0 0 0 1 / ],
    [ qw/ 0 0 0 0 0 / ],
);


if( 
    defined( 
        my $result = find_first_sideways( \@array )
    )
) {
    say "First row containing all zeros is $result.";
} else { 
    say "No rows found to contain all zeros.";
}


sub find_first_sideways {
    my $matrix  =  shift;
    my @scan    =  ( 0 .. $#{ $matrix } );
    my $depth = 0;
    while( @scan > 0 and $depth < @{ $matrix->[0] } ) {
        @scan = grep{ $matrix->[$_][$depth] == 0 } @scan;
        $depth++;
    }
    if( defined( $scan[0] ) ) {
        return $scan[0];
    } else {
        return undef;
    }
}