From 4eebc07786114e281c00a6002eb0183daa35e0f4 Mon Sep 17 00:00:00 2001
From: Lubos Kolouch <lubos@kolouch.net>
Date: Sun, 21 May 2023 13:26:30 +0200
Subject: feat(challenge-071/lubos-kolouch/perl,python/ch-1,-ch-2): Challenge
 071 LK Perl Python

---
 challenge-071/lubos-kolouch/perl/ch-1.pl   | 23 +++++++++
 challenge-071/lubos-kolouch/perl/ch-2.pl   | 77 ++++++++++++++++++++++++++++++
 challenge-071/lubos-kolouch/python/ch-1.py | 26 ++++++++++
 challenge-071/lubos-kolouch/python/ch-2.py | 52 ++++++++++++++++++++
 4 files changed, 178 insertions(+)
 create mode 100644 challenge-071/lubos-kolouch/perl/ch-1.pl
 create mode 100644 challenge-071/lubos-kolouch/perl/ch-2.pl
 create mode 100644 challenge-071/lubos-kolouch/python/ch-1.py
 create mode 100644 challenge-071/lubos-kolouch/python/ch-2.py

diff --git a/challenge-071/lubos-kolouch/perl/ch-1.pl b/challenge-071/lubos-kolouch/perl/ch-1.pl
new file mode 100644
index 0000000000..5499ab959b
--- /dev/null
+++ b/challenge-071/lubos-kolouch/perl/ch-1.pl
@@ -0,0 +1,23 @@
+#!/usr/bin/perl
+use strict;
+use warnings;
+
+sub find_peaks {
+    my @arr = @_;
+    my $n   = scalar @arr;
+
+    my @peaks;
+    push @peaks, $arr[0] if $arr[0] > $arr[1];
+
+    for my $i ( 1 .. $n - 2 ) {
+        push @peaks, $arr[$i] if $arr[$i] > $arr[ $i - 1 ] and $arr[$i] > $arr[ $i + 1 ];
+    }
+
+    push @peaks, $arr[-1] if $arr[-1] > $arr[-2];
+
+    return @peaks;
+}
+
+# Tests
+print join( ", ", find_peaks( 18, 45, 38, 25, 10, 7, 21, 6,  28, 48 ) ), "\n";    # 48, 45, 21
+print join( ", ", find_peaks( 47, 11, 32, 8,  1,  9, 39, 14, 36, 23 ) ), "\n";    # 47, 32, 39, 36
diff --git a/challenge-071/lubos-kolouch/perl/ch-2.pl b/challenge-071/lubos-kolouch/perl/ch-2.pl
new file mode 100644
index 0000000000..1f8970ad3b
--- /dev/null
+++ b/challenge-071/lubos-kolouch/perl/ch-2.pl
@@ -0,0 +1,77 @@
+#!/usr/bin/perl
+use strict;
+use warnings;
+
+package Node;
+
+sub new {
+    my ( $class, $data ) = @_;
+    my $self = {
+        data => $data,
+        next => undef
+    };
+    return bless $self, $class;
+}
+
+package LinkedList;
+
+sub new {
+    my ($class) = @_;
+    my $self = { head => undef };
+    return bless $self, $class;
+}
+
+sub append {
+    my ( $self, $data ) = @_;
+    my $new_node = Node->new($data);
+    if ( !$self->{head} ) {
+        $self->{head} = $new_node;
+    }
+    else {
+        my $cur = $self->{head};
+        $cur = $cur->{next} while $cur->{next};
+        $cur->{next} = $new_node;
+    }
+}
+
+sub remove_from_end {
+    my ( $self, $n ) = @_;
+    my $size = 0;
+    my $cur  = $self->{head};
+    while ($cur) {
+        $size++;
+        $cur = $cur->{next};
+    }
+    if ( $n >= $size ) {
+        $self->{head} = $self->{head}->{next};
+    }
+    else {
+        $cur = $self->{head};
+        for ( 1 .. $size - $n - 1 ) {
+            $cur = $cur->{next};
+        }
+        $cur->{next} = $cur->{next}->{next} if $cur->{next};
+    }
+}
+
+sub print {
+    my ($self) = @_;
+    my @values;
+    my $cur = $self->{head};
+    while ($cur) {
+        push @values, $cur->{data};
+        $cur = $cur->{next};
+    }
+    print join( " -> ", @values ), "\n";
+}
+
+# Tests
+my $ll = LinkedList->new();
+for my $i ( 1 .. 5 ) {
+    $ll->append($i);
+}
+
+for my $i ( 1 .. 6 ) {
+    $ll->remove_from_end($i);
+    $ll->print();
+}
diff --git a/challenge-071/lubos-kolouch/python/ch-1.py b/challenge-071/lubos-kolouch/python/ch-1.py
new file mode 100644
index 0000000000..7a92d52f8b
--- /dev/null
+++ b/challenge-071/lubos-kolouch/python/ch-1.py
@@ -0,0 +1,26 @@
+#!/usr/bin/env python
+# -*- coding: utf-8 -*-
+
+from typing import List
+
+
+def find_peaks(arr: List[int]) -> List[int]:
+    n = len(arr)
+    # Initialize peaks list with the first element if it's bigger than the second
+    peaks = [arr[0]] if arr[0] > arr[1] else []
+
+    # Iterate over the array checking for peaks
+    for i in range(1, n-1):
+        if arr[i] > arr[i-1] and arr[i] > arr[i+1]:
+            peaks.append(arr[i])
+
+    # Add the last element if it's bigger than the penultimate
+    if arr[-1] > arr[-2]:
+        peaks.append(arr[-1])
+
+    return peaks
+
+
+# Tests
+print(find_peaks([18, 45, 38, 25, 10, 7, 21, 6, 28, 48]))  # [48, 45, 21]
+print(find_peaks([47, 11, 32, 8, 1, 9, 39, 14, 36, 23]))  # [47, 32, 39, 36]
diff --git a/challenge-071/lubos-kolouch/python/ch-2.py b/challenge-071/lubos-kolouch/python/ch-2.py
new file mode 100644
index 0000000000..5662d38226
--- /dev/null
+++ b/challenge-071/lubos-kolouch/python/ch-2.py
@@ -0,0 +1,52 @@
+class Node:
+    def __init__(self, data=None):
+        self.data = data
+        self.next = None
+
+
+class LinkedList:
+    def __init__(self):
+        self.head = None
+
+    def append(self, data):
+        if not self.head:
+            self.head = Node(data)
+        else:
+            cur = self.head
+            while cur.next:
+                cur = cur.next
+            cur.next = Node(data)
+
+    def remove_from_end(self, n):
+        if self.head is None:
+            return
+        size = 0
+        cur = self.head
+        while cur:
+            size += 1
+            cur = cur.next
+        if n >= size:
+            self.head = self.head.next if self.head.next else None
+        else:
+            cur = self.head
+            for _ in range(size - n - 1):
+                cur = cur.next
+            cur.next = cur.next.next if cur.next and cur.next.next else None
+
+    def __str__(self):
+        values = []
+        cur = self.head
+        while cur:
+            values.append(str(cur.data))
+            cur = cur.next
+        return ' -> '.join(values)
+
+
+# Tests
+ll = LinkedList()
+for i in range(1, 6):
+    ll.append(i)
+
+for i in range(1, 7):
+    ll.remove_from_end(i)
+    print(ll)
-- 
cgit