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| -rw-r--r-- | challenge-210/bob-lied/perl/ch-2.pl | 84 |
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diff --git a/challenge-210/bob-lied/perl/ch-2.pl b/challenge-210/bob-lied/perl/ch-2.pl new file mode 100644 index 0000000000..e24099670d --- /dev/null +++ b/challenge-210/bob-lied/perl/ch-2.pl @@ -0,0 +1,84 @@ +#!/usr/bin/env perl +# vim:set ts=4 sw=4 sts=4 et ai wm=0 nu: +#============================================================================= +# ch-2.pl Perl Weekly Challenge 210 Task 2 Number Collision +#============================================================================= +# Copyright (c) 2023, Bob Lied +#============================================================================= +# You are given an array of integers which can move in right direction if it +# is positive and left direction when negative. If two numbers collide then +# the smaller one will explode. And if both are same then they both explode. +# We take the absolute value in consideration when comparing. +# All numbers move at the same speed, therefore any 2 numbers moving in the +# same direction will never collide. +# Write a script to find out who survives the collision. +# Example 1: Input: @list = (2, 3, -1) Output: (2, 3) +# The numbers 3 and -1 collide and -1 explodes in the end. +# So we are left with (2, 3). +# Only positive numbers are left, so no more collisions will happen. +# Example 2: Input: @list = (3, 2, -4) Output: (-4) +# The numbers 2 and -4 collide and 2 explodes in the end. +# That gives us (3, -4). +# Now the numbers 3 and -4 collide and 3 explodes. +# Finally we are left with -4. +# Example 3: Input: @list = (1, -1) Output: () +# The numbers 1 and -1 both collide and explode. Nothing left in the end. +#============================================================================= + +use v5.36; + +use builtin qw/true false/; no warnings "experimental::builtin"; + +use Getopt::Long; +my $Verbose = 0; +my $DoTest = 0; + +GetOptions("test" => \$DoTest, "verbose" => \$Verbose); +exit(!runTest()) if $DoTest; + +say "(", join(',', numberCollision(@ARGV)->@*), ")"; + +sub numberCollision(@list) +{ + my $collision = true; + while ( $collision ) + { + $collision = false; + for ( my $i = 0 ; $i < $#list ; $i++ ) + { + my ($left, $right) = @list[$i, $i+1]; + next unless ( $left >= 0 && $right < 0 ); + + $collision = true; + if ( abs($left) == abs($right) ) + { + # Both explode + splice(@list, $i, 2); + } + else + { + my $keep = ( abs($left) > abs($right) ? $left : $right ); + # Replace the pair with the larger one + splice(@list, $i, 2, $keep); + } + } + } + return [ @list ]; +} + +sub runTest +{ + use Test2::V0; + + is( numberCollision(2,3,-1), [2,3], "Example 1"); + is( numberCollision(3,2,-4), [ -4], "Example 2"); + is( numberCollision(1, -1), [ ], "Example 3"); + + is( numberCollision(1 ), [ 1 ], "Singleton"); + is( numberCollision(1,2,3 ), [ 1,2,3 ], "No collision positive"); + is( numberCollision(-1,-2,-3 ), [ -1,-2,-3 ], "No collision negative"); + is( numberCollision(-1,-2,3,4 ), [ -1,-2,3,4 ], "No collision"); + + done_testing; +} + |