- Added solutions by E. Choroba.

- Added solutions by Dave Jacoby.
- Added solutions by Matthew Neleigh.
- Added solutions by Luca Ferrari.
- Added solutions by Roger Bell_West.
- Added solutions by Mariano Spadacinni.
- Added solutions by Bob Lied.
- Added solutions by Peter Meszaros.
- Added solutions by Jaldhar H. Vyas.
- Added solutions by Robbie Hatley.
- Added solutions by Athanasius.
- Added solutions by Ali Moradi.
- Added solutions by Clifton Wood.
- Added solutions by Ulrich Rieke.
- Added solutions by Peter Campbell Smith.

14 files changed, 320 insertions, 0 deletions

diff --git a/challenge-243/clifton-wood/raku/ch-1.raku b/challenge-243/clifton-wood/raku/ch-1.raku
new file mode 100644
index 0000000000..9c87a02298
--- /dev/null
+++ b/challenge-243/clifton-wood/raku/ch-1.raku
@@ -0,0 +1,16 @@
+my @p1 = (1, 3, 2, 3, 1);
+my @p2 = (2, 4, 3, 5, 1);
+
+sub reverse-pair (@a) {
+  #A reverse pair is a pair (i, j) where: a) 0 <= i < j < nums.length and b) nums[i] > 2 * nums[j].
+  for @a.keys.combinations(2).map( *.sort.cache ).unique.cache {
+    if @a[ .head ] > 2 * @a[ .tail ] {
+      say "({ .head }, { .tail }) => num[{ .head }] ({ @a[ .head ] }) = {
+             @a[.head ] } > 2 * num[{ .tail }] ({ @a[ .tail ] })";
+    }
+  }
+  say '-' x 40;
+}
+
+reverse-pair( @p1 );
+reverse-pair( @p2 );
diff --git a/challenge-243/clifton-wood/raku/ch-2.raku b/challenge-243/clifton-wood/raku/ch-2.raku
new file mode 100644
index 0000000000..399b79d450
--- /dev/null
+++ b/challenge-243/clifton-wood/raku/ch-2.raku
@@ -0,0 +1,6 @@
+sub floor-sums (*@a) {
+  (@a X @a).map({ ( .head / .tail ).floor }).sum.say
+}
+
+floor-sums(2, 5, 9);
+floor-sums( |(7 xx 7) );
diff --git a/challenge-243/eric-cheung/python/ch-1.py b/challenge-243/eric-cheung/python/ch-1.py
new file mode 100755
index 0000000000..9ee2534f4b
--- /dev/null
+++ b/challenge-243/eric-cheung/python/ch-1.py
@@ -0,0 +1,18 @@
+

+from itertools import combinations

+

+def IsReversePair (arrInput):

+    if arrInput[0] > 2 * arrInput[1]:

+        return True

+    return False

+

+

+## arrNum = [1, 3, 2, 3, 1]  ## Example 1

+arrNum = [2, 4, 3, 5, 1]  ## Example 2

+

+

+arrCombList = combinations(arrNum, 2)

+arrOutputList = [arrLoop for arrLoop in list(arrCombList) if IsReversePair(arrLoop)]

+

+

+print (len(arrOutputList))

diff --git a/challenge-243/eric-cheung/python/ch-2.py b/challenge-243/eric-cheung/python/ch-2.py
new file mode 100755
index 0000000000..8d186c9bf5
--- /dev/null
+++ b/challenge-243/eric-cheung/python/ch-2.py
@@ -0,0 +1,13 @@
+

+from itertools import combinations

+

+def GetFloorSum (arrInput):

+    return int(arrInput[0] / arrInput[1]) + int(arrInput[1] / arrInput[0])

+

+## arrNum = [2, 5, 9]  ## Example 1

+arrNum = [7, 7, 7, 7, 7, 7, 7]  ## Example 2

+

+arrCombList = combinations(arrNum, 2)

+nSum = len(arrNum) + sum([GetFloorSum(arrLoop) for arrLoop in list(arrCombList)])

+

+print (nSum)

diff --git a/challenge-243/ulrich-rieke/cpp/ch-1.cpp b/challenge-243/ulrich-rieke/cpp/ch-1.cpp
new file mode 100755
index 0000000000..52de66f21a
--- /dev/null
+++ b/challenge-243/ulrich-rieke/cpp/ch-1.cpp
@@ -0,0 +1,36 @@
+#include <vector>
+#include <iostream>
+#include <string>
+
+std::vector<std::string> split( const std::string & startline , 
+      const std::string & sep ) {
+   std::vector<std::string> separated ;
+   std::string::size_type start { 0 } ;
+   std::string::size_type pos ;
+   do {
+      pos = startline.find_first_of( sep , start ) ;
+      separated.push_back( startline.substr( start , pos - start ) ) ;
+      start = pos + 1 ;
+   } while ( pos != std::string::npos ) ;
+   return separated ;
+}
+
+int main( ) {
+   std::cout << "Please enter some integers, separated by blanks!\n" ;
+   std::string line ;
+   std::getline( std::cin , line ) ;
+   std::vector<std::string> numberstrings { split ( line , " ") } ;
+   std::vector<int> numbers ;
+   for ( auto & s : numberstrings ) 
+      numbers.push_back( std::stoi( s ) ) ;
+   int sum = 0 ;
+   int size = numbers.size( ) ;
+   for ( int i = 0 ; i < size - 1 ; i++ ) {
+      for ( int j = i + 1 ; j < size ; j++ ) {
+	 if ( numbers[ i ] > 2 * numbers[ j ] ) 
+	    sum++ ;
+      }
+   }
+   std::cout << sum << std::endl ;
+   return 0 ;
+}
diff --git a/challenge-243/ulrich-rieke/cpp/ch-2.cpp b/challenge-243/ulrich-rieke/cpp/ch-2.cpp
new file mode 100755
index 0000000000..27a6f46268
--- /dev/null
+++ b/challenge-243/ulrich-rieke/cpp/ch-2.cpp
@@ -0,0 +1,49 @@
+#include <iostream>
+#include <vector>
+#include <string>
+#include <algorithm>
+
+std::vector<std::string> split( const std::string & startline , 
+      const std::string & sep ) {
+   std::vector<std::string> separated ;
+   std::string::size_type start { 0 } ;
+   std::string::size_type pos ;
+   do {
+      pos = startline.find_first_of( sep , start ) ;
+      separated.push_back( startline.substr( start , pos - start ) ) ;
+      start = pos + 1 ;
+   } while ( pos != std::string::npos ) ;
+   return separated ;
+}
+
+int main( ) {
+   std::cout << "Enter an array of positive integers >= 1 , separated by blanks!\n" ;
+   std::string line ;
+   std::getline( std::cin , line ) ;
+   std::vector<std::string> numberstrings { split( line , " " ) } ;
+   std::vector<int> numbers ;
+   for ( auto & s : numberstrings ) 
+      numbers.push_back( std::stoi( s ) ) ;
+   int comparedTo { numbers[ 0 ] } ;
+   int len = numbers.size( ) ;
+   if ( std::all_of( numbers.begin( ) , numbers.end( ) , [comparedTo]( int i ) {
+	    return i == comparedTo ; } ) ) {
+      std::cout << comparedTo * len << std::endl ;
+   }
+   else {
+      int sum = 0 ;
+      for ( int i = 0 ; i < len ; i++ ) {
+	 sum += 1 ; // representing the floor of dividing a number by itself
+	 if ( i < len - 1 ) {
+	    for ( int j = i + 1 ; j < len ; j++ ) {
+	       if ( numbers[ i ] != numbers[ j ] ) {
+		  sum += numbers[ i ] / numbers[ j ] ;
+		  sum += numbers[ j ] / numbers[ i ] ;
+	       }
+	    }
+	 }
+      }
+      std::cout << sum << std::endl ;
+   }
+   return 0 ;
+}
diff --git a/challenge-243/ulrich-rieke/haskell/ch-1.hs b/challenge-243/ulrich-rieke/haskell/ch-1.hs
new file mode 100755
index 0000000000..7b5dcfab25
--- /dev/null
+++ b/challenge-243/ulrich-rieke/haskell/ch-1.hs
@@ -0,0 +1,17 @@
+module Challenge243
+   where
+import Data.List ( (!!) ) 
+
+findGreater :: [Int] -> Int -> Int
+findGreater list index = length $ filter (\n -> (list !! index ) > ( 2 * n ) )
+ $ drop (index + 1 ) list    
+
+solution :: [Int] -> Int
+solution list = sum $ map (\i -> findGreater list i ) [0..length list - 2]
+
+main :: IO ( )
+main = do
+   putStrLn "Enter some integers, separated by blanks!" 
+   numberstrings <- getLine
+   let numbers = map read $ words numberstrings
+   print $ solution numbers
diff --git a/challenge-243/ulrich-rieke/haskell/ch-2.hs b/challenge-243/ulrich-rieke/haskell/ch-2.hs
new file mode 100755
index 0000000000..225a4f23b5
--- /dev/null
+++ b/challenge-243/ulrich-rieke/haskell/ch-2.hs
@@ -0,0 +1,25 @@
+module Challenge243_2
+   where
+import Data.List ( (!!) ) 
+
+findPairs :: [Int] -> [(Int , Int) ] 
+findPairs list = concat $ map (\i -> map (\el -> (list !! i , el )) $ drop ( i + i ) 
+ list ) [0..length list - 2]
+
+solution :: [Int] -> Int
+solution list 
+   |all (\i -> i == h ) list = h * ( length list )
+   |otherwise = length list + ( sum $ map (\p -> div (fst p ) ( snd p) + div
+    ( snd p ) ( fst p ) ) suitablePairs ) 
+   where
+    h :: Int
+    h = head list
+    suitablePairs :: [(Int , Int ) ]
+    suitablePairs = filter (\pa -> fst pa /= snd pa ) $ findPairs list
+
+main :: IO ( )
+main = do
+   putStrLn "Enter some positive integers >= 1 , separated by blanks!" 
+   numberstrings <- getLine
+   let numbers = map read $ words numberstrings
+   print $ solution numbers
diff --git a/challenge-243/ulrich-rieke/perl/ch-1.pl b/challenge-243/ulrich-rieke/perl/ch-1.pl
new file mode 100755
index 0000000000..825fe2cd05
--- /dev/null
+++ b/challenge-243/ulrich-rieke/perl/ch-1.pl
@@ -0,0 +1,19 @@
+#!/usr/bin/perl ;

+use strict ;

+use warnings ;

+use feature 'say' ;

+

+say "Enter some integers, separated by blanks!" ;

+my $line = <STDIN> ;

+chomp $line ;

+my @numbers = split( /\s/ , $line ) ;

+my $len = scalar( @numbers ) ;

+my $sum = 0 ;

+for my $i ( 0..$len - 2 ) {

+   for my $j ( $i + 1 .. $len - 1 ) {

+      if ( $numbers[ $i ] > 2 * $numbers[ $j ] ) {

+	 $sum++ ;

+      }

+   }

+}

+say $sum ;
\ No newline at end of file
diff --git a/challenge-243/ulrich-rieke/perl/ch-2.pl b/challenge-243/ulrich-rieke/perl/ch-2.pl
new file mode 100755
index 0000000000..1ebbdc078b
--- /dev/null
+++ b/challenge-243/ulrich-rieke/perl/ch-2.pl
@@ -0,0 +1,29 @@
+#!/usr/bin/perl ;

+use strict ;

+use warnings ;

+use feature 'say' ;

+use POSIX ;

+

+say "Enter some integers >= 1 , separated by blanks!" ;

+my $line = <STDIN> ;

+chomp $line ;

+my @numbers = split( /\s/ , $line ) ;

+my $len = scalar( @numbers ) ;

+if ( scalar( grep { $_ == $numbers[ 0 ] } @numbers ) == $len ) {

+   say ( $numbers[ 0 ] * $len ) ;

+}

+else {

+   my $sum = 0 ;

+   for my $i ( 0..$len - 1 ) {

+      $sum += 1 ; # representing the floor of dividing a number by itself

+      if ( $i < $len - 1 ) {

+	 for my $j ( $i + 1 .. $len - 1 ) {

+	    if ( $numbers[ $i ] != $numbers[ $j ] ) {

+	       $sum += floor( $numbers[ $i ] / $numbers[ $j ] ) ;

+	       $sum += floor( $numbers[ $j ] / $numbers[ $i ] ) ;

+	    }

+	 }

+      }

+   }

+   say $sum ;

+}
\ No newline at end of file
diff --git a/challenge-243/ulrich-rieke/raku/ch-1.raku b/challenge-243/ulrich-rieke/raku/ch-1.raku
new file mode 100755
index 0000000000..2a70ebaefc
--- /dev/null
+++ b/challenge-243/ulrich-rieke/raku/ch-1.raku
@@ -0,0 +1,15 @@
+use v6 ;
+
+say "Enter some integers, separated by blanks!" ;
+my $line = $*IN.get ;
+my @numbers = $line.words.map( {.Int} ) ;
+my $sum = 0 ;
+my $len = @numbers.elems ;
+for (0..$len - 2 ) -> $i {
+   for ( $i + 1 .. $len - 1 ) -> $j {
+      if ( @numbers[ $i ] > 2 * @numbers[ $j ] ) {
+	 $sum++ ;
+      }
+   }
+}
+$sum.say ;
diff --git a/challenge-243/ulrich-rieke/raku/ch-2.raku b/challenge-243/ulrich-rieke/raku/ch-2.raku
new file mode 100755
index 0000000000..40f762fde9
--- /dev/null
+++ b/challenge-243/ulrich-rieke/raku/ch-2.raku
@@ -0,0 +1,24 @@
+use v6 ;
+
+say "Enter some integers >= 1, separated by blanks!" ;
+my $line = $*IN.get ;
+my @numbers = $line.words.map( {.Int} ) ;
+my $len = @numbers.elems ;
+if ( @numbers.grep( { $_ == @numbers[0] } ).elems == $len ) {
+   say ( @numbers[ 0 ] * $len ) ;
+}
+else {
+   my $sum = 0 ;
+   for (0..$len - 1 ) -> $i {
+      $sum += @numbers[ $i ] div @numbers[ $i ] ;
+      if ( $i < $len - 1 ) {
+	 for ( $i + 1 .. $len - 1 ) -> $j {
+	    if ( @numbers[ $i ] != @numbers[ $j ] ) {
+	       $sum += @numbers[ $i ] div @numbers[ $j ] ;
+	       $sum += @numbers[ $j ] div @numbers[ $i ] ;
+	    }
+	 }
+      }
+   }
+   $sum.say ;
+}
diff --git a/challenge-243/ulrich-rieke/rust/ch-1.rs b/challenge-243/ulrich-rieke/rust/ch-1.rs
new file mode 100755
index 0000000000..2ea91301dc
--- /dev/null
+++ b/challenge-243/ulrich-rieke/rust/ch-1.rs
@@ -0,0 +1,20 @@
+use std::io ;
+
+fn main() {
+    println!("Enter some integers , separated by blanks!");
+    let mut inline : String = String::new( ) ;
+    io::stdin( ).read_line( &mut inline ).unwrap( ) ;
+    let entered_line : &str = &*inline ;
+    let numbers : Vec<i32> = entered_line.split_whitespace( ).map( | s | 
+	  s.trim( ).parse::<i32>().unwrap( ) ).collect( ) ;
+    let len = numbers.len( ) ;
+    let mut sum : usize = 0 ;
+    for i in 0..len - 1 {
+       for j in i + 1..len {
+	  if numbers[ i ] > 2 * numbers[ j ] {
+	     sum += 1 ;
+	  }
+       }
+    }
+    println!("{}" , sum ) ;
+}
diff --git a/challenge-243/ulrich-rieke/rust/ch-2.rs b/challenge-243/ulrich-rieke/rust/ch-2.rs
new file mode 100755
index 0000000000..3c62208f0e
--- /dev/null
+++ b/challenge-243/ulrich-rieke/rust/ch-2.rs
@@ -0,0 +1,33 @@
+use std::io ;
+
+fn main() {
+    println!("Enter some integers >= 1 , separated by blanks!");
+    let mut inline : String = String::new( ) ;
+    io::stdin( ).read_line( & mut inline ).unwrap( ) ;
+    let entered_line : &str = &*inline ;
+    let numbers : Vec<i32> = entered_line.split_whitespace( ).map( | s | 
+	  s.trim( ).parse::<i32>().unwrap( ) ).collect( ) ;
+    if numbers.iter( ).all( | n | *n == numbers[ 0 ] ) {
+       println!("{}" , numbers[ 0 ] * ( numbers.len( ) as i32 ) ) ;
+    }
+    else {
+       let len : usize = numbers.len( ) ;
+       let mut sum : i32 = 0 ;
+       for i in 0..len {
+	  sum += numbers[ i ] / numbers[ i ] ;
+	  if i < len - 1 {
+	     for j in i + 1..len {
+		if numbers[ i ] != numbers[ j ] {
+		   let mut the_floor : i32 = ((numbers[ i ] as f32 ) / ( 
+			 numbers[j ] as f32 )).floor( ) as i32 ;
+		   sum += the_floor ;
+		   the_floor = ((numbers[ j ] as f32 ) / ( numbers[ i ] as 
+			 f32 )).floor( ) as i32 ;
+		   sum += the_floor ;
+		}
+	     }
+	  }
+       }
+       println!("{}" , sum ) ;
+    }
+}