Merge pull request #13005 from PerlBoy1967/branch-for-challenge-345

w345 - Task 1 & 2 (Perl)

2 files changed, 90 insertions, 0 deletions

diff --git a/challenge-345/perlboy1967/perl/ch1.pl b/challenge-345/perlboy1967/perl/ch1.pl
new file mode 100755
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+++ b/challenge-345/perlboy1967/perl/ch1.pl
@@ -0,0 +1,33 @@
+#!/bin/perl
+
+=pod
+
+L<https://theweeklychallenge.org/blog/perl-weekly-challenge-345#TASK1>
+
+Author: Niels 'PerlBoy' van Dijke
+
+Task 1: Peak Positions
+Submitted by: Mohammad Sajid Anwar
+
+You are given an array of integers, @ints.
+
+Find all the peaks in the array, a peak is an element that is strictly
+greater than its left and right neighbours. Return the indices of all such
+peak positions.
+
+=cut
+
+use Test2::V0 qw(-no_srand);
+use exact 'v5.32', -signatures;
+
+sub peakPositions (@ints) {
+  map { $ints[$_-1] < $ints[$_] > $ints[$_+1] ? $_ : () } 1 .. $#ints - 1;
+}
+
+is([peakPositions(1,3,2)],[1],'Example 1');
+is([peakPositions(2,4,6,5,3)],[2],'Example 2');
+is([peakPositions(1,2,3,2,4,1)],[2,4],'Example 3');
+is([peakPositions(5,3,1)],[],'Example 4');
+is([peakPositions(1,5,1,5,1,5,1)],[1,3,5],'Example 5');
+
+done_testing;
diff --git a/challenge-345/perlboy1967/perl/ch2.pl b/challenge-345/perlboy1967/perl/ch2.pl
new file mode 100755
index 0000000000..1621f26920
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+++ b/challenge-345/perlboy1967/perl/ch2.pl
@@ -0,0 +1,57 @@
+#!/bin/perl
+
+=pod
+
+L<https://theweeklychallenge.org/blog/perl-weekly-challenge-345#TASK2>
+
+Author: Niels 'PerlBoy' van Dijke
+
+Task 2: Last Visitor
+Submitted by: Mohammad Sajid Anwar
+
+You are given an integer array @ints where each element is either a positive integer or -1.
+
+We process the array from left to right while maintaining two lists:
+
+|| @seen: stores previously seen positive integers (newest at the front)
+|| @ans: stores the answers for each -1
+
+Rules:
+
+If $ints[i] is a positive number -> insert it at the front of @seen
+If $ints[i] is -1:
+
+Let $x be how many -1s in a row we’ve seen before this one.
+
+If $x < len(@seen) -> append seen[x] to @ans
+
+Else -> append -1 to @ans
+
+At the end, return @ans.
+
+=cut
+
+use Test2::V0 qw(-no_srand);
+use exact 'v5.32', -signatures;
+
+sub lastVisitor  (@ints) {
+  my ($i,@seen,@ans) = (0);
+  for (@ints) {
+    if ($_ >= 0) {
+      push(@seen,$_);
+      $i++ if ($i < 0);
+    } else {
+      $i += $_ if (@seen);
+      push(@ans,$seen[$i] // -1);
+    } 
+  }
+  return @ans;
+}
+
+is([lastVisitor(5,-1,-1)],[5,-1],'Example 1');
+is([lastVisitor(3,7,-1,-1,-1)],[7,3,-1],'Example 2');
+is([lastVisitor(2,-1,4,-1,-1)],[2,4,2],'Example 3');
+is([lastVisitor(10,20,-1,30,-1,-1)],[20,30,20],'Example 4');
+is([lastVisitor(-1,-1,5,-1)],[-1,-1,5],'Example 5');
+
+done_testing;