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Diffstat (limited to 'challenge-086/duncan-c-white/perl/ch-1.pl')
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diff --git a/challenge-086/duncan-c-white/perl/ch-1.pl b/challenge-086/duncan-c-white/perl/ch-1.pl new file mode 100755 index 0000000000..9281cebb0a --- /dev/null +++ b/challenge-086/duncan-c-white/perl/ch-1.pl @@ -0,0 +1,65 @@ +#!/usr/bin/perl +# +# Task 1: "Pair Difference +# +# You are given an array of integers @N and an integer $A. +# +# Write a script to find find if there exists a pair of elements in the +# array whose difference is $A. Print 1 if exists otherwise 0. +# +# Example 1: +# +# Input: @N = (10, 8, 12, 15, 5) and $A = 7 +# Output: 1 as 15 - 8 = 7 +# +# Example 2: +# +# Input: @N = (1, 5, 2, 9, 7) and $A = 6 +# Output: 1 as 7 - 1 = 6 +# +# Example 3: +# +# Input: @N = (10, 30, 20, 50, 40) and $A = 15 +# Output: 0 +# +# My notes: simple and straightforward: try all pairs of elements looking +# for abs(x-y)==A +# + +use strict; +use warnings; +use feature 'say'; +use Function::Parameters; +use Data::Dumper; +use Getopt::Long; + +my $debug = 0; +die "Usage: pair-diff [--debug] DIFF array\n" unless + GetOptions( "debug" => \$debug ) && + @ARGV>1; +my( $diff, @x ) = @ARGV; + +# +# my $found = finddiff( $diff, @x ); +# Attempt to find any two elements of @x with difference $diff; +# return 1 iff such a pair of elements exists (0 otherwise). +# +fun finddiff( $diff, @x ) +{ + foreach my $apos (0..$#x-1) + { + my $a = $x[$apos]; + foreach my $bpos ($apos+1..$#x) + { + my $b = $x[$bpos]; + next unless abs($a-$b) == $diff; + say "found $a and $b with diff $diff" if $debug; + return 1; + } + } + return 0; +} + + +my $found = finddiff( $diff, @x ); +say $found; |