#!/usr/bin/perl
use warnings;
use strict;

my @indices = qw( 1.1 1.4 5.33 6.1 7.23 7.133 10 11 );

sub i_le {
    my ($x, $y) = @_;
    my ($x_line, $x_char) = split /\./, $x;
    my ($y_line, $y_char) = split /\./, $y;
    $_ //= 0 for $x_char, $y_char;
    return $x_line < $y_line 
        || $x_line == $y_line && $x_char <= $y_char
}

sub range {
    my ($in) = @_;
    for my $i (0 .. $#indices / 2) {
        return @indices[$i * 2, $i * 2 + 1]
            if i_le($indices[ $i * 2 ], $in)
            && i_le($in, $indices[ $i * 2 + 1 ]);
    }
}

use Test::More tests => 5;
is_deeply [range('1.1')], [qw[ 1.1 1.4 ]];
is_deeply [range('1.2')], [qw[ 1.1 1.4 ]];
is_deeply [range('1.4')], [qw[ 1.1 1.4 ]];
is_deeply [range('7.50')], [qw[ 7.23 7.133 ]];
is_deeply [range('10.5')], [qw[ 10 11 ]];