Challenge 078
Table of Contents
Task 1 - Leader Element
You are given an array @A containing distinct integers.
Write a script to find all leader elements in the array @A. Print (0) if none found.
- An element is leader if it is greater than all the elements to its right side.
Perl
- Program: perl/ch-1.pl
We take input from @ARGV, loop over it. And then we loop over the
elements at right, goto next if $arg is less than $elm. This will push
all the leader elements to @leader.
my @leader; MAIN: while (my $arg = shift @ARGV) { foreach my $elm (@ARGV) { next MAIN if $arg < $elm; } push @leader, $arg; }
Task 2 - Left Rotation
You are given array @A containing positive numbers and @B containing one or more indices from the array @A.
Write a script to left rotate @A so that the number at the first index of @B becomes the first element in the array. Similary, left rotate @A again so that the number at the second index of @B becomes the first element in the array.
Perl
- Program: perl/ch-2.pl
Loop over @B & then rotate the elements. Same could've been done with
Left Rotation, I find this easier to understand.
my @A = qw(10 20 30 40 50); my @B = qw(3 4); foreach (@B) { my @tmp = @A; foreach (1 ... scalar @tmp - $_) { unshift @tmp, pop @tmp; } print join(', ', @tmp), "\n"; }