#! perl -slw
use strict;
use List::Util qw[ sum ];

our $N ||= 1_000;
our $SCALE ||= 100;

sub pickGen {
    my $total = sum @_;
    my $accum = 0;
    my @weights = map{
        my $fencepost = $_[ $_ ] * $SCALE / $total;
        ( ( $_ ) x $fencepost, $accum += $fencepost )
    } 0 .. $#_;
    return sub {
        my $randValue = rand $SCALE;
        my $index = $weights[ $randValue ];
        return $index if $index == int $index;
        return $weights[ int( $randValue + ( $randValue <=> $index ) ) ]
    };
}

my @array = (
    ["foo",  1],
    ["bar",  3],
    ["baz",  4],
    ["quux", 9]
);

my $picker = pickGen( map $_->[1], @array );

my %choices;
$choices{ $array[ $picker->() ][ 0 ] }++ for 1 .. $N;

printf "%10s frequency %.3f%%\n", $_, $choices{ $_ } *100 / $N
    for sort{ $choices{ $a } <=> $choices{ $b } } keys %choices;