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| -rw-r--r-- | challenge-201/bob-lied/README | 4 | ||||
| -rw-r--r-- | challenge-201/bob-lied/perl/ch-1.pl | 70 |
2 files changed, 72 insertions, 2 deletions
diff --git a/challenge-201/bob-lied/README b/challenge-201/bob-lied/README index 3d4521e11d..3c3241bd85 100644 --- a/challenge-201/bob-lied/README +++ b/challenge-201/bob-lied/README @@ -1,4 +1,4 @@ -Solutions to weekly challenge 200 by Bob Lied +Solutions to weekly challenge 201 by Bob Lied -https://perlweeklychallenge.org/blog/perl-weekly-challenge-200/ +https://perlweeklychallenge.org/blog/perl-weekly-challenge-201/ https://github.com/boblied/perlweeklychallenge-club/tree/master/challenge-200/bob-lied diff --git a/challenge-201/bob-lied/perl/ch-1.pl b/challenge-201/bob-lied/perl/ch-1.pl new file mode 100644 index 0000000000..eacbd4b736 --- /dev/null +++ b/challenge-201/bob-lied/perl/ch-1.pl @@ -0,0 +1,70 @@ +#!/usr/bin/env perl +# vim:set ts=4 sw=4 sts=4 et ai wm=0 nu: +#============================================================================= +# ch-1.pl Perl Weekly Challenge Week 201 Task 1 Missing Numbers +#============================================================================= +# Copyright (c) 2023, Bob Lied +#============================================================================= +# You are given an array of unique numbers. +# Write a script to find out all missing numbers in the range 0..$n +# where $n is the array size. +# Example 1 Input: @array = (0,1,3) Output: 2 +# The array size i.e. total element count is 3, so the range is 0..3. +# The missing number is 2 in the given array. +# Example 2 Input: @array = (0,1) Output: 2 +# The array size is 2, therefore the range is 0..2. +# The missing number is 2. +#============================================================================= + +use v5.36; + +use Getopt::Long; +my $Verbose = 0; +my $DoTest = 0; + +GetOptions("test" => \$DoTest, "verbose" => \$Verbose); +exit(!runTest()) if $DoTest; + +# Take anything that looks list-ish as arguments, squash it together +# and remove punctuation. What's left should be a string of numbers. +# Split that string on white space to get a list of numbers. This +# is too rough -- it distorts negative numbers and decimal points, but +# good enough for the examples and some quick tests. +my $list = "@ARGV"; +$list =~ s/[[:punct:]]/ /g; + +say join(' ', missingNumber( [ split(' ', $list) ] )->@* ); + +sub missingNumber($list) +{ + # Make a hash where the keys are numbers 0 .. n. Start out assuming + # that every number is missing. Note that $# works on references. + my $n = 1 + $#{$list}; + my %missing = map { $_ => 1 } 0 .. $n; + + # The ones in the list are not missing. Numbers that are out + # of range would be silently ignored in delete, but just to be + # explicit, let's only delete things that actually exist. + # This convenient syntax of 0<x<n is a feature of Perl 5.32. + delete $missing{$_} for grep { 0 <= $_ <= $n } $list->@*; + + # Sort isn't actually required. + return [ sort { $a <=> $b } keys %missing ]; +} + +sub runTest +{ + use Test2::V0; + + is( missingNumber( [ 0,1,3 ] ), [ 2 ], "Example 1"); + is( missingNumber( [ 0,1 ] ), [ 2 ], "Example 2"); + + is( missingNumber( [ 2,3 ] ), [ 0,1 ], "Missing head"); + is( missingNumber( [ 0,1,9 ] ), [ 2,3 ], "Missing tail"); + is( missingNumber( [ 0,5,3,1 ] ), [ 2,4 ], "Missing multiple"); + is( missingNumber( [ 8,9 ] ), [ 0,1,2 ], "Missing whole range"); + is( missingNumber( [ 3,-1 ] ), [ 0,1,2 ], "Missing negative"); + + done_testing; +} + |