- Added solutions by Ulrich Rieke.

- Added solutions by Robert DiCicco.
- Added solutions by Eric Cheung.
- Added solutions by Laurent Rosenfeld.
- Added solutions by Wanderdoc.
- Added solutions by W. Luis Mochan.
- Added solutions by E. Choroba.
- Added solutions by David Ferrone.
- Added solutions by Mark Anderson.
- Added solutions by rcmlz.
- Added solutions by Peter Campbell Smith.
- Added solutions by PokGoPun.
- Added solutions by Thomas Kohler.
- Added solutions by Lubos Kolouch.
- Added solutions by Luca Ferrari.
- Added solutions by Jaldhar H. Vyas.

34 files changed, 3640 insertions, 2507 deletions

diff --git a/challenge-236/eric-cheung/python/ch-1.py b/challenge-236/eric-cheung/python/ch-1.py
new file mode 100755
index 0000000000..87c8692ed0
--- /dev/null
+++ b/challenge-236/eric-cheung/python/ch-1.py
@@ -0,0 +1,29 @@
+

+## arrInputBill = [5, 5, 5, 10, 20]  ## Example 1

+## arrInputBill = [5, 5, 10, 10, 20]  ## Example 2

+arrInputBill = [5, 5, 5, 20]  ## Example 3

+

+arrChange = [0, 0, 0]

+bSucceed = True

+

+for nIndx in range(len(arrInputBill)):    

+    if arrInputBill[nIndx] == 5:

+        arrChange[0] = arrChange[0] + 1

+    elif arrInputBill[nIndx] == 10:

+        if arrChange[0] < 1:

+            bSucceed = False

+            break

+        arrChange[0] = arrChange[0] - 1

+        arrChange[1] = arrChange[1] + 1

+    elif arrInputBill[nIndx] == 20:

+        if arrChange[0] < 3 and (arrChange[0] < 1 or arrChange[1] < 1):

+            bSucceed = False

+            break

+        arrChange[2] = arrChange[2] + 1

+        if arrChange[1] > 0:

+            arrChange[1] = arrChange[1] - 1

+            arrChange[0] = arrChange[0] - 1

+        else:

+            arrChange[0] = arrChange[0] - 3

+

+print (bSucceed)

diff --git a/challenge-236/eric-cheung/python/ch-2.py b/challenge-236/eric-cheung/python/ch-2.py
new file mode 100755
index 0000000000..c503507ba1
--- /dev/null
+++ b/challenge-236/eric-cheung/python/ch-2.py
@@ -0,0 +1,24 @@
+

+arrInput = [4, 6, 3, 8, 15, 0, 13, 18, 7, 16, 14, 19, 17, 5,  11,  1,  12,  2,  9,  10]  ## Example 1

+## arrInput = [0, 1, 13, 7, 6, 8, 10, 11, 2, 14, 16, 4, 12, 9, 17, 5, 3, 18, 15, 19]  ## Example 2

+## arrInput = [9, 8, 3, 11, 5, 7, 13, 19, 12, 4, 14, 10, 18, 2, 16, 1, 0, 15, 6, 17]  ## Example 3

+

+arrIndx = [0] * len(arrInput)

+arrOutput = []

+

+for nIndxLoop in range(len(arrIndx)):

+    if arrIndx[nIndxLoop] == 1:

+        continue

+

+    arrTemp = []

+    nTempIndxLoop = nIndxLoop

+

+    while arrInput[nTempIndxLoop] not in arrTemp:

+        arrTemp.append(arrInput[nTempIndxLoop])

+        arrIndx[nTempIndxLoop] = 1

+        nTempIndxLoop = arrInput[nTempIndxLoop]

+

+    arrOutput.append(arrTemp)

+

+## print (arrOutput)

+print (len(arrOutput))

diff --git a/challenge-236/laurent-rosenfeld/blog.txt b/challenge-236/laurent-rosenfeld/blog.txt
new file mode 100644
index 0000000000..8fcccd56d0
--- /dev/null
+++ b/challenge-236/laurent-rosenfeld/blog.txt
@@ -0,0 +1 @@
+https://blogs.perl.org/users/laurent_r/2023/09/perl-weekly-challenge-236-array-loops.html
diff --git a/challenge-236/laurent-rosenfeld/perl/ch-2.pl b/challenge-236/laurent-rosenfeld/perl/ch-2.pl
new file mode 100644
index 0000000000..d0937e17a6
--- /dev/null
+++ b/challenge-236/laurent-rosenfeld/perl/ch-2.pl
@@ -0,0 +1,20 @@
+use strict;
+use warnings;
+use feature 'say';
+
+sub find_loops {
+    my @in = @_;
+    my $count = 0;
+    for my $i (0..$#in) {
+        my $j = $i;
+        # say $i;
+        while (1) {
+            last unless defined $in[$j];
+            # say "\t", $j, "\t", @in[$j];
+            ++$count and last if $in[$j] == $i;
+            $j = $in[$j];
+        }
+    }
+    return $count;
+}
+
diff --git a/challenge-236/laurent-rosenfeld/raku/ch-2.raku b/challenge-236/laurent-rosenfeld/raku/ch-2.raku
new file mode 100644
index 0000000000..0241c93c49
--- /dev/null
+++ b/challenge-236/laurent-rosenfeld/raku/ch-2.raku
@@ -0,0 +1,24 @@
+sub find-loops (@in) {
+    my $count = 0;
+    for 0..@in.end -> $i {
+        my $j = $i;
+        loop {
+            last unless @in[$j].defined;
+            # say "\t", $j, "\t", @in[$j];
+            ++$count and last if @in[$j] == $i;
+            $j = @in[$j];
+        }
+    }
+    return $count;
+}
+
+my @tests =
+    (4,6,3,8,15,0,13,18,7,16,14,19,17,5,11,1,12,2,9,10),
+    (0,1,13,7,6,8,10,11,2,14,16,4,12,9,17,5,3,18,15,19),
+    (9,8,3,11,5,7,13,19,12,4,14,10,18,2,16,1,0,15,6,17),
+    (0,1,13,7,6,8,10,11,2,14,16,4,12,9,17,5,3);
+
+for @tests -> @test {
+    say @test;
+    say "\tNumber of loops: ", find-loops @test;
+}
diff --git a/challenge-236/rcmlz/raku/ch-1.raku b/challenge-236/rcmlz/raku/ch-1.raku
new file mode 100644
index 0000000000..ca8a45ecf0
--- /dev/null
+++ b/challenge-236/rcmlz/raku/ch-1.raku
@@ -0,0 +1,48 @@
+unit module rcmlz::raku::task-one:ver<0.0.1>:auth<github:rcmlz>:api<1>;
+
+# run in terminal: raku --optimize=3 -I challenge-nr236/rcmlz/raku/ -- test/challenge-nr236/raku/task-one.rakutest
+# or               raku --optimize=3 -I challenge-nr236 -- test/benchmark-scalabiity.raku --task=task-one --user=rcmlz --max-run-times=1,3,7 --max-problem=10 --v=True --test-before-benchmark=True --out-folder=/tmp nr236; cat /tmp/nr236_task-one.csv
+
+#|[
+You are asked to sell juice each costs $5. 
+You are given an array of bills. 
+You can only sell ONE juice to each customer but make sure you return exact change back. 
+You only have $5, $10 and $20 notes. 
+You do not have any change in hand at first.
+
+- Write a script to find out if it is possible to sell to each customers with correct change.
+]
+our sub solution(@input --> Bool) is export {
+	my $n = @input;
+
+	my %change =
+		5 => 0,
+		10 => 0,
+		20 => 0
+	;
+
+	my $i = 0;
+	while (%change.values).all >= 0 and $i < $n {
+		given @input[$i++] {
+			when 5  { 
+					 	%change<5>++
+				    } 
+			when 10 { 
+					 	%change<5>--; 
+					 	%change<10>++
+					} 
+			when 20 { 
+						if %change<10> {
+					  		%change<10>--
+					  	}else {
+					  		%change<5>--;
+					  		%change<5>--
+					  	}
+					  	%change<5>--
+					} 
+			default { die  "$_ : only 5, 10 and 20 as input is accepted!"}
+		}
+	}
+
+	(%change.values).all >= 0 ?? True !! False
+}
\ No newline at end of file
diff --git a/challenge-236/rcmlz/raku/ch-2.raku b/challenge-236/rcmlz/raku/ch-2.raku
new file mode 100644
index 0000000000..13571552ec
--- /dev/null
+++ b/challenge-236/rcmlz/raku/ch-2.raku
@@ -0,0 +1,36 @@
+unit module rcmlz::raku::task-two:ver<0.0.1>:auth<github:rcmlz>:api<1>;
+
+# run in terminal: raku --optimize=3 -I challenge-nr236/rcmlz/raku/ -- test/challenge-nr236/raku/task-two.rakutest
+# or               raku --optimize=3 -I challenge-nr236 -- test/benchmark-scalabiity.raku --task=task-two --user=rcmlz --max-run-times=1,3,7 --max-problem=10 --v=True --test-before-benchmark=True --out-folder=/tmp nr236; cat /tmp/nr236_task-two.csv
+
+#|[
+You are given an array of unique integers.
+
+- Write a script to determine how many loops are in the given array.
+- To determine a loop: Start at an index and take the number at array[index]
+  and then proceed to that index and continue this until you end up at the starting index.
+]
+our sub solution(@input) is export {
+    my %graph = @input.pairs;
+    my $cycles = 0;
+
+    while %graph.keys.elems {
+        
+        $cycles = $cycles + %graph.grep( -> $entry {$entry.key == $entry.value} );
+
+        %graph = %graph.grep( -> $entry {$entry.key != $entry.value} );        
+
+        my $untouched = %graph.keys.Set;
+
+        for %graph.kv -> $k, $v {
+            if %graph{$v}:exists {
+                %graph{$k} = %graph{$v};
+                $untouched = $untouched ∖ $k;
+            }
+        }
+
+        %graph{$_}:delete for $untouched.keys;
+    }
+
+    return $cycles;
+}
\ No newline at end of file
diff --git a/challenge-236/robert-dicicco/julia/ch-1.jl b/challenge-236/robert-dicicco/julia/ch-1.jl
new file mode 100644
index 0000000000..9650b34e02
--- /dev/null
+++ b/challenge-236/robert-dicicco/julia/ch-1.jl
@@ -0,0 +1,55 @@
+#!/usr/bin/env julia
+#=
+--------------------------------------
+AUTHOR: Robert DiCicco
+DATE  : 2023-09-25
+Challenge 236 Task 01 Exact Change ( Julia )
+-------------------------------------
+=#
+
+using Printf
+
+bills = [[5, 5, 5, 10, 20], [5, 5, 10, 10, 20],[5, 5, 5, 20]]
+
+for paid in bills
+    @printf("Input: @bills = %s\n", paid)
+    cnt = 1
+    change = 0
+    while cnt <=length(paid)
+        ticket = paid[cnt]
+        change_required = ticket - 5
+        if ticket == 5
+            change += 5
+        elseif ticket == 10
+            change += 0
+        elseif ticket == 20
+            if change_required > change
+                @printf("Output: false\n\n")
+                break
+            else
+                @printf("Output: true\n\n")
+                break
+            end
+            change -= 10
+        end
+        cnt += 1
+    end
+end
+
+#=
+--------------------------------------
+SAMPLE OUTPUT
+julia .\ExactChange.jl
+
+Input: @bills = [5, 5, 5, 10, 20]
+Output: true
+
+Input: @bills = [5, 5, 10, 10, 20]
+Output: false
+
+Input: @bills = [5, 5, 5, 20]
+Output: true
+-------------------------------------
+=#
+
+
diff --git a/challenge-236/robert-dicicco/perl/ch-1.pl b/challenge-236/robert-dicicco/perl/ch-1.pl
new file mode 100644
index 0000000000..be79d7d4de
--- /dev/null
+++ b/challenge-236/robert-dicicco/perl/ch-1.pl
@@ -0,0 +1,56 @@
+#!/usr/bin/env perl
+use v5.38;
+=begin comment
+--------------------------------------
+AUTHOR: Robert DiCicco
+DATE  : 2023-09-25
+Challenge 236 Task 01 Exact Change ( Perl )
+-------------------------------------
+=cut
+
+my @bills = ([5, 5, 5, 10, 20], [5, 5, 10, 10, 20],[5, 5, 5, 20]);
+
+for my $chg (@bills) {
+    say "Input: \@bills = [@$chg]";
+    my $ln = scalar @$chg;
+    my $cnt = 0;
+    my $change = 0;
+    while ($cnt < @$chg) {
+        my $ticket = $chg->[$cnt];
+        my $change_required = $ticket - 5;
+        if ($ticket == 5){
+            $change += 5;
+        } elsif ($ticket == 10) {
+            $change -= 5;
+            $change += 5;
+        } elsif ($ticket == 20) {
+            if ($change_required > $change){
+                say "Output: false\n";
+                last;
+            } else {
+                say "Output: true\n";
+                last;
+            }
+            $change -= 15;
+            $change += 5;
+        }
+        $cnt++;
+    }
+}
+=begin comment
+--------------------------------------
+SAMPLE OUTPUT
+perl .\ExactChange.pl
+
+Input: @bills = [5 5 5 10 20]
+Output: true
+
+Input: @bills = [5 5 10 10 20]
+Output: false
+
+Input: @bills = [5 5 5 20]
+Output: true
+-------------------------------------
+=cut
+
+
diff --git a/challenge-236/robert-dicicco/powershell/ch-1.psl b/challenge-236/robert-dicicco/powershell/ch-1.psl
new file mode 100644
index 0000000000..ba05daec08
--- /dev/null
+++ b/challenge-236/robert-dicicco/powershell/ch-1.psl
@@ -0,0 +1,53 @@
+<#
+--------------------------------------------------
+AUTHOR: Robert DiCicco
+DATE  : 2023-09-25
+Challenge 236 Task 01 Exact Change ( Powershell )
+--------------------------------------------------
+#>
+
+$bills = @( (5, 5, 5, 10, 20), (5, 5, 10, 10, 20),(5, 5, 5, 20))
+
+foreach  ($paid in $bills ) {
+    write-host "Input: @bills = [$paid]"
+    $cnt = 0
+    $change = 0
+    $ln = $paid.Length
+    while ( $cnt -lt $ln ) {
+        $ticket = $paid[$cnt]
+        $change_required = $ticket - 5
+        switch ($ticket) {
+            5 {$change += 5}
+            10 {}
+            20 {
+                if ($change_required -gt $change) {
+                    write-host "Output: false`n"
+                    break
+                } else {
+                    write-host "Output: true`n"
+                    break
+                }
+            }
+        }
+        $cnt += 1
+    }
+}
+
+<#
+--------------------------------------------------
+SAMPLE OUTPUT
+.\ExactChange.ps1
+
+Input: @bills = [5 5 5 10 20]
+Output: true
+
+Input: @bills = [5 5 10 10 20]
+Output: false
+
+Input: @bills = [5 5 5 20]
+Output: true
+--------------------------------------------------
+#>
+
+
+
diff --git a/challenge-236/robert-dicicco/python/ch-1.py b/challenge-236/robert-dicicco/python/ch-1.py
new file mode 100644
index 0000000000..7f1521f673
--- /dev/null
+++ b/challenge-236/robert-dicicco/python/ch-1.py
@@ -0,0 +1,50 @@
+#!/usr/bin/env python
+'''
+--------------------------------------
+AUTHOR: Robert DiCicco
+DATE  : 2023-09-25
+Challenge 236 Task 01 Exact Change ( Python )
+-------------------------------------
+'''
+bills = [[5, 5, 5, 10, 20], [5, 5, 10, 10, 20],[5, 5, 5, 20]]
+
+for paid in bills:
+    print(f"Input: @bills = {paid}")
+    cnt = 0
+    change = 0
+    while cnt < len(paid):
+        ticket = paid[cnt]
+        change_required = ticket - 5
+        if ticket == 5:
+            change += 5
+        elif ticket == 10:
+            change += 0
+        elif ticket == 20:
+            if change_required > change:
+                print("Output: false\n")
+                break
+            else:
+                print("Output: true\n")
+                break
+            change -= 10
+        cnt += 1
+
+'''
+--------------------------------------
+SAMPLE OUTPUT
+python .\ExactChange.py
+
+Input: @bills = [5, 5, 5, 10, 20]
+Output: true
+
+Input: @bills = [5, 5, 10, 10, 20]
+Output: false
+
+Input: @bills = [5, 5, 5, 20]
+Output: true
+-------------------------------------
+'''
+
+
+
+
diff --git a/challenge-236/robert-dicicco/raku/ch-1.raku b/challenge-236/robert-dicicco/raku/ch-1.raku
new file mode 100644
index 0000000000..77664be74b
--- /dev/null
+++ b/challenge-236/robert-dicicco/raku/ch-1.raku
@@ -0,0 +1,56 @@
+#!/usr/bin/env raku
+use v6;
+
+=begin comment
+--------------------------------------
+AUTHOR: Robert DiCicco
+DATE  : 2023-09-25
+Challenge 236 Task 01 Exact Change ( Raku )
+-------------------------------------
+=end comment
+
+my @bills = ([5, 5, 5, 10, 20], [5, 5, 10, 10, 20],[5, 5, 5, 20]);
+
+for (@bills) -> @chg {
+    say "Input: \@bills = ",@chg;
+    my $cnt = 0;
+    my $change = 0;
+    while ($cnt < @chg.elems) {
+        my $ticket = @chg[$cnt];
+        my $change_required = $ticket - 5;
+        if $ticket == 5 {
+            $change += 5;
+        } elsif $ticket == 10 {
+            $change += 0;
+        } elsif $ticket == 20 {
+            if $change_required > $change {
+                say "Output: false\n";
+                last;
+            } else {
+                say "Output: true\n";
+                last;
+            }
+            $change -= 10;
+        }
+        $cnt++;
+    }
+}
+
+=begin comment
+--------------------------------------
+SAMPLE OUTPUT
+raku .\ExactChange.rk
+
+Input: @bills = [5 5 5 10 20]
+Output: true
+
+Input: @bills = [5 5 10 10 20]
+Output: false
+
+Input: @bills = [5 5 5 20]
+Output: true
+-------------------------------------
+=end comment
+
+
+
diff --git a/challenge-236/robert-dicicco/ruby/ch-1.rb b/challenge-236/robert-dicicco/ruby/ch-1.rb
new file mode 100644
index 0000000000..160a48363f
--- /dev/null
+++ b/challenge-236/robert-dicicco/ruby/ch-1.rb
@@ -0,0 +1,57 @@
+#!/usr/bin/env ruby
+=begin
+--------------------------------------
+AUTHOR: Robert DiCicco
+DATE  : 2023-09-25
+Challenge 236 Task 01 Exact Change ( Ruby )
+-------------------------------------
+=end
+
+bills = [[5, 5, 5, 10, 20], [5, 5, 10, 10, 20],[5, 5, 5, 20]]
+
+bills.each do |paid|
+    puts("Input: @bills = #{paid}")
+    cnt = 0
+    change = 0
+    while cnt < paid.length()
+        ticket = paid[cnt]
+        change_required = ticket - 5
+        cnt += 1
+        case ticket
+        when 5
+            change += 5
+        when 10
+            # pass
+        when 20
+            if change_required > change
+                puts("Output: false\n\n")
+                break
+            else
+                puts("Output: true\n\n")
+                break
+            end
+            change -= 10
+        end
+    end
+    cnt += 1
+end
+
+=begin
+--------------------------------------
+SAMPLE OUTPUT
+ruby .\ExactChange.rb
+
+Input: @bills = [5, 5, 5, 10, 20]
+Output: true
+
+Input: @bills = [5, 5, 10, 10, 20]
+Output: false
+
+Input: @bills = [5, 5, 5, 20]
+Output: true
+-------------------------------------
+=end
+
+
+
+
diff --git a/challenge-236/robert-dicicco/tcl/ch-1.tcl b/challenge-236/robert-dicicco/tcl/ch-1.tcl
new file mode 100644
index 0000000000..a6e97d6699
--- /dev/null
+++ b/challenge-236/robert-dicicco/tcl/ch-1.tcl
@@ -0,0 +1,58 @@
+#!/usr/bin/env tclsh
+set comment {
+--------------------------------------
+AUTHOR: Robert DiCicco
+DATE  : 2023-09-25
+Challenge 236 Task 01 Exact Change ( Tcl )
+-------------------------------------
+}
+
+set bills { { 5 5 5 10 20 } { 5 5 10 10 20 } { 5 5 5 20 } }
+
+foreach paid $bills {
+    puts "Input: @bills = ($paid)"
+    set cnt 0
+    set change 0
+    set ln [expr [llength $paid]]
+    while { [ expr $cnt ] < $ln } {
+        set ticket [lindex $paid $cnt]
+        set change_required [expr $ticket - 5]
+        switch $ticket {
+            5 {
+                set change [ expr $change + 5 ]
+            }
+            10 {
+            }
+            20 {
+                if { $change_required > $change  } {
+                    puts "Output: false\n"
+                    break
+                } else {
+                    puts "Output: true\n"
+                    break
+                }
+                set change [ expr $change - 10]
+            }
+        }
+        set cnt [expr $cnt + 1]
+    }
+    set cnt 0
+}
+
+set comment {
+--------------------------------------
+SAMPLE OUTPUT
+tclsh .\ExactChange.tcl
+
+Input: @bills = ( 5 5 5 10 20 )
+Output: true
+
+Input: @bills = ( 5 5 10 10 20 )
+Output: false
+
+Input: @bills = ( 5 5 5 20 )
+Output: true
+-------------------------------------
+}
+
+
diff --git a/challenge-236/ulrich-rieke/cpp/ch-2.cpp b/challenge-236/ulrich-rieke/cpp/ch-2.cpp
new file mode 100755
index 0000000000..17a7d6bd94
--- /dev/null
+++ b/challenge-236/ulrich-rieke/cpp/ch-2.cpp
@@ -0,0 +1,38 @@
+#include <iostream>

+#include <vector>

+#include <numeric>

+#include <set>

+#include <algorithm>

+

+//my assumption is that you can always find a loop if the starting array 

+//is a random shuffle of all the indices of a vector from 0 to len - 1 where

+//len is the length of the array. 

+

+int main( ) {

+   std::vector<int> numbers( 20 ) ;

+   std::iota( numbers.begin( ) , numbers.end( ) , 1 ) ;

+   std::random_shuffle( numbers.begin( ) , numbers.end( ) ) ;

+   int loops = 0 ;

+   for ( int pos = 0 ; pos < 20 ; pos++ ) {

+      if ( numbers[ pos ] == pos ) { 

+	 loops++ ;

+      }

+      else {

+	 std::set<int> already_seen ;

+	 int num = numbers[ pos ] ;

+	 auto p = already_seen.insert( num ) ;

+	 while ( p.second ) {

+	    if ( already_seen.find( num ) != already_seen.end( ) ) {

+	       loops++ ;

+	       break ;

+	    }

+	    else {

+	       num = numbers[ num ] ;

+	       p = already_seen.insert( num ) ;

+	    }

+	 }

+      }

+   }

+   std::cout << loops << std::endl ;

+   return 0 ;

+}

diff --git a/challenge-236/ulrich-rieke/rust/ch-2.rs b/challenge-236/ulrich-rieke/rust/ch-2.rs
new file mode 100755
index 0000000000..17724298c3
--- /dev/null
+++ b/challenge-236/ulrich-rieke/rust/ch-2.rs
@@ -0,0 +1,42 @@
+use std::io ;
+use std::collections::HashSet ;
+
+fn main() {
+    println!("Enter some unique positive integers!");
+    println!("They should be a random shuffle of integers from 0 to array length!") ;
+    let mut inline : String = String::new( ) ;
+    io::stdin( ).read_line( &mut inline ).unwrap( ) ;
+    let entered_line : &str = &*inline ;
+    let numbers : Vec<usize> = entered_line.split_whitespace( ).map( | s | 
+	  s.trim( ).parse::<usize>( ).unwrap( ) ).collect( ) ;
+    let mut loops : usize = 0 ;
+    //the strategy is as follows : if a number in the array represents its own 
+    //index, it is a loop in itself , and the number of loops can be increased
+    //otherwise: for every index in the vector, we build a set of numbers we fill
+    //by adding numbers from numbers[current_index]. If we cannot add a number 
+    //to the set because it is already there no loop can be formed at that index.
+    //Otherwise we continue until, eventually, numbers[current_index] == start_index
+    for pos in 0..numbers.len( ) {
+       if numbers[ pos ] == pos {
+	  loops += 1 ;
+       }
+       else {
+	  let mut already_seen : HashSet<usize> = HashSet::new( ) ;
+	  let mut num : usize = numbers[ pos ] ; 
+	  let mut inserted : bool = already_seen.insert( num ) ;
+	  'inner: while inserted {
+	     println!("{:?}" , already_seen ) ;
+	     if already_seen.contains( &pos ) {
+		loops += 1 ;
+		break 'inner ;
+	     }
+	     else {
+		num = numbers[ num ] ;
+		inserted = already_seen.insert( num ) ;
+	     }
+	  }
+       }
+    }
+    println!("{}" , loops) ;
+}
+
diff --git a/challenge-236/wanderdoc/perl/ch-1.pl b/challenge-236/wanderdoc/perl/ch-1.pl
new file mode 100755
index 0000000000..1647898986
--- /dev/null
+++ b/challenge-236/wanderdoc/perl/ch-1.pl
@@ -0,0 +1,70 @@
+#!perl

+use strict;

+use warnings FATAL => qw(all);

+

+=prompt

+You are asked to sell juice each costs $5. You are given an array of bills. You can only sell ONE juice to each customer but make sure you return exact change back. You only have $5, $10 and $20 notes. You do not have any change in hand at first. 

+Write a script to find out if it is possible to sell to each customers with correct change.

+Example 1 Input: @bills = (5, 5, 5, 10, 20) Output: true

+From the first 3 customers, we collect three $5 bills in order.

+From the fourth customer, we collect a $10 bill and give back a $5.

+From the fifth customer, we give a $10 bill and a $5 bill.

+Since all customers got correct change, we output true.

+

+Example 2 Input: @bills = (5, 5, 10, 10, 20) Output: false

+From the first two customers in order, we collect two $5 bills.

+For the next two customers in order, we collect a $10 bill and give back a $5 bill.

+For the last customer, we can not give the change of $15 back because we only have two $10 bills.

+Since not every customer received the correct change, the answer is false.

+=cut

+

+use Test2::V0;

+

+sub exact_change

+{

+     my @bills = @_;

+     my %change;

+     for my $bill ( @bills )

+     {

+          if ( $bill == 5 )

+          {

+               $change{$bill}++;

+          }

+          elsif ( $bill == 10 )

+          {

+               if ( $change{5} > 0 )

+               {

+                    $change{$bill}++;

+                    $change{5}--;

+               }

+               else

+               {

+                    return 'false';

+               }

+          }

+          elsif ( $bill == 20 )

+          {

+               if ( $change{5} > 2 ) 

+               { 

+                    $change{$bill}++; 

+                    $change{5} -= 3; 

+               }

+               elsif ( $change{5} > 0 and $change{10} > 0 )

+               {

+                    $change{$bill}++;

+                    $change{5}--;

+                    $change{10}--;

+               }

+               else

+               {

+                    return 'false';

+               }

+          }

+     }

+     return 'true';

+}

+

+

+is(exact_change(5, 5, 5, 10, 20), 'true', 'Example 1');

+is(exact_change(5, 5, 10, 10, 20), 'false', 'Example 2');

+done_testing();

diff --git a/challenge-236/wanderdoc/perl/ch-2.pl b/challenge-236/wanderdoc/perl/ch-2.pl
new file mode 100755
index 0000000000..df05db485f
--- /dev/null
+++ b/challenge-236/wanderdoc/perl/ch-2.pl
@@ -0,0 +1,102 @@
+#!perl

+use strict;