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| -rwxr-xr-x | challenge-072/bob-lied/perl/ch-1.pl | 93 |
1 files changed, 93 insertions, 0 deletions
diff --git a/challenge-072/bob-lied/perl/ch-1.pl b/challenge-072/bob-lied/perl/ch-1.pl new file mode 100755 index 0000000000..367eb1d957 --- /dev/null +++ b/challenge-072/bob-lied/perl/ch-1.pl @@ -0,0 +1,93 @@ +#!/usr/bin/env perl +# vim:set ts=4 sw=4 sts=4 et ai wm=0 nu: +#============================================================================= +# ch-1.pl +#============================================================================= +# Copyright (c) 2020, Bob Lied +#============================================================================= +# Perl Weekly Challenge 72 Task 1 Trailing Zeroes +#============================================================================= +# +# You are given a positive integer $N (<= 10). +# Write a script to print number of trailing zeroes in $N!. + +use strict; +use warnings; +use feature qw(say); + +use Getopt::Long; + +sub Usage { "Usage: $0 N\n\tN <= 10" } + + +sub trailingZero +{ + my ($n) = @_; + return int($n/5); +} + +use Memoize; +memoize('_fact'); + +sub _fact +{ + my ($product, $n) = @_; + return $product if $n < 2; + return _fact($n*$product, $n-1); +} + +sub factorial +{ + my ($n) = @_; + return 1 if $n < 2; + return _fact($n, $n-1); +} + +sub runTests +{ + use Test::More; + + is ( factorial( 0), 1, "f( 0)" ); + is ( factorial( 1), 1, "f( 1)" ); + is ( factorial( 2), 2, "f( 2)" ); + is ( factorial( 3), 6, "f( 3)" ); + is ( factorial( 4), 24, "f( 4)" ); + is ( factorial( 5), 120, "f( 5)" ); + is ( factorial( 6), 720, "f( 6)" ); + is ( factorial( 7), 5040, "f( 7)" ); + is ( factorial( 8), 40320, "f( 8)" ); + is ( factorial( 9), 362880, "f( 9)" ); + is ( factorial(10), 3628800, "f(10)" ); + is ( factorial(15), 1307674368000, "f(15)" ); + is ( factorial(20), 2432902008176640000, "f(20)" ); + + is( trailingZero( 0), 0, "for 0"); + is( trailingZero( 1), 0, "for 1"); + is( trailingZero( 2), 0, "for 2"); + is( trailingZero( 3), 0, "for 3"); + is( trailingZero( 4), 0, "for 4"); + is( trailingZero( 5), 1, "for 5"); + is( trailingZero( 6), 1, "for 6"); + is( trailingZero( 7), 1, "for 7"); + is( trailingZero( 8), 1, "for 8"); + is( trailingZero( 9), 1, "for 9"); + is( trailingZero(10), 2, "for 10"); + is( trailingZero(20), 4, "for 20"); + + done_testing(); + +} + +########## main + +my $doTest; +GetOptions('test!' => \$doTest); + +exit(!runTests()) if $doTest; + +die Usage unless scalar(@ARGV) == 1; + +my $N = shift; +die Usage unless $N > 0 && $N <= 10; + +say trailingZero($N); |