sgreen solutions to challenge 172

6 files changed, 156 insertions, 1 deletions

diff --git a/challenge-172/sgreen/README.md b/challenge-172/sgreen/README.md
index 512411c9b5..327abfe81e 100644
--- a/challenge-172/sgreen/README.md
+++ b/challenge-172/sgreen/README.md
@@ -1 +1,3 @@
-# The Weekly Challenge 170
+# The Weekly Challenge 172
+
+[Blog](https://dev.to/simongreennet/weekly-challenge-172-1h8i)
diff --git a/challenge-172/sgreen/blog.txt b/challenge-172/sgreen/blog.txt
new file mode 100644
index 0000000000..30f3a52cdd
--- /dev/null
+++ b/challenge-172/sgreen/blog.txt
@@ -0,0 +1 @@
+https://dev.to/simongreennet/weekly-challenge-172-1h8i
diff --git a/challenge-172/sgreen/perl/ch-1.pl b/challenge-172/sgreen/perl/ch-1.pl
new file mode 100755
index 0000000000..30fa1e424a
--- /dev/null
+++ b/challenge-172/sgreen/perl/ch-1.pl
@@ -0,0 +1,47 @@
+#!/usr/bin/env perl
+
+use strict;
+use warnings;
+use feature 'say';
+use experimental 'signatures';
+
+use List::Util 'sum';
+use Algorithm::Combinatorics 'combinations';
+
+sub is_prime ($number) {
+    # Return true or false if the number is a prime
+    if ( $number < 2 ) {
+        return;
+    }
+
+    foreach my $i ( 2 .. sqrt($number) ) {
+        if ( $number % $i == 0 ) {
+            return;
+        }
+    }
+
+    # It's a prime
+    return 1;
+}
+
+sub main ( $m, $n ) {
+    # Retrieve a list of all prime numbers <= m
+    my @primes = ();
+    for ( my $i = $m ; $i > 1 ; $i-- ) {
+        push @primes, $i if is_prime($i);
+    }
+
+    # Go through each combination of n length, and see if we have a solution
+    my $iter = combinations( \@primes, $n );
+    while ( my $c = $iter->next ) {
+        if ( sum(@$c) == $m ) {
+            say join ', ', @$c;
+            return;
+        }
+    }
+
+    # It is possible that no solution is found
+    say 'No solution!';
+}
+
+main(@ARGV);
diff --git a/challenge-172/sgreen/perl/ch-2.pl b/challenge-172/sgreen/perl/ch-2.pl
new file mode 100755
index 0000000000..d55ed5c7f5
--- /dev/null
+++ b/challenge-172/sgreen/perl/ch-2.pl
@@ -0,0 +1,35 @@
+#!/usr/bin/env perl
+
+use strict;
+use warnings;
+use feature 'say';
+use experimental 'signatures';
+
+sub get_value ( $l, $quart ) {
+    # Calculate the position of the value we require
+    my $pos = ($#$l) * $quart / 100;
+    my $i   = int($pos);
+
+    if ( $i == $pos ) {
+        # It is a single value
+        return $l->[$i];
+    }
+
+    # We need the average of two numbers
+    return ( $l->[$i] + $l->[ $i + 1 ] ) / 2;
+}
+
+sub main (@l) {
+    # Sort the list
+    @l = sort { $a <=> $b } @l;
+    my @solution = ();
+
+    # Calculate the five values
+    foreach my $quart ( 0, 25, 50, 75, 100 ) {
+        push @solution, get_value( \@l, $quart );
+    }
+
+    say join ', ', @solution;
+}
+
+main(@ARGV);
diff --git a/challenge-172/sgreen/python/ch-1.py b/challenge-172/sgreen/python/ch-1.py
new file mode 100755
index 0000000000..125ec64815
--- /dev/null
+++ b/challenge-172/sgreen/python/ch-1.py
@@ -0,0 +1,36 @@
+#!/usr/bin/env python
+
+import sys
+import math
+from itertools import combinations
+
+
+def is_prime(number):
+    '''Return true or false if the number is a prime'''
+    if number < 2:
+        return False
+
+    for i in range(2, int(math.sqrt(number)) + 1):
+        if number % i == 0:
+            return False
+
+    # It's a prime
+    return True
+
+
+def main(m, n):
+    # Retrieve a list of all prime numbers <= m
+    primes = [x for x in range(m, 1, -1) if is_prime(x)]
+
+    # Go through each combination of n length, and see if we have a solution
+    for l in combinations(primes, n):
+        if sum(l) == m:
+            print(l, sep=', ')
+            return
+
+    # It is possible that no solution is found
+    print('No solution!')
+
+
+if __name__ == '__main__':
+    main(int(sys.argv[1]), int(sys.argv[2]))
diff --git a/challenge-172/sgreen/python/ch-2.py b/challenge-172/sgreen/python/ch-2.py
new file mode 100755
index 0000000000..c9162d1604
--- /dev/null
+++ b/challenge-172/sgreen/python/ch-2.py
@@ -0,0 +1,34 @@
+#!/usr/bin/env python
+
+import sys
+
+
+def get_value(l, quart):
+    # Calculate the position of the value we require
+    pos = (len(l)-1) * quart / 100
+    i = int(pos)
+
+    if i == pos:
+        # It is a single value
+        return l[i]
+
+    # We need the average of two numbers
+    val = (l[i] + l[i+1]) / 2
+    return int(val) if int(val) == val else val
+
+
+def main(l):
+
+    # Sort the list
+    l = sorted([int(x) for x in l])
+    solution = []
+
+    # Calculate the five values
+    for quart in range(0, 101, 25):
+        solution.append(get_value(l, quart))
+
+    print(*solution, sep=', ')
+
+
+if __name__ == '__main__':
+    main(sys.argv[1:])