perl glyph_odds [ministry level] [trials]

glyph_odds.pl

#!/usr/bin/perl 
use 5.12.2;
use List::Util qw(reduce sum);

sub factorial {
    my ($in) = @_;
    return 1 unless $in;
    return reduce { $a * $b } ( 1 .. $in );
}

sub nCx {
    my ( $n, $x ) = @_;
    return factorial($n) / ( factorial($x) * factorial( $n - $x ) );
}

# P(x) = nCx * p^x * q^(n-x)
#
#   n = number of trials
#   x = number of successes among n trials
#   p = probability of success in any one trial
#   q = probability of failure in any one trial (q = 1 - p)

sub single_trial {
    my ( $n, $x, $p ) = @_;
    my $q = 1 - $p;
    my $out = nCx( $n, $x ) * ( $p**$x ) * $q**( $n - $x );
    # say "nCx( $n, $x ) * ( $p**$x ) * $q**( $n - $x ) = " . $out;
    return $out;
}

my ( $level, $trials ) = @ARGV;

my $odds = $level / 100;

say sum map { single_trial( $trials, $_, $odds ) } 1 .. $trials;