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━━━━━━━━━━━━━━━
CHALLENGE 078
━━━━━━━━━━━━━━━
Table of Contents
─────────────────
1 Task 1 - Leader Element
.. 1.1 Perl
2 Task 2 - Left Rotation
.. 2.1 Perl
1 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.
1.1 Perl
────────
• Program: [file: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;
│ }
└────
2 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.
2.1 Perl
────────
• Program: [file: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";
│ }
└────
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