12 files changed, 240 insertions, 0 deletions
diff --git a/challenge-144/lubos-kolouch/perl/ch-1.pl b/challenge-144/lubos-kolouch/perl/ch-1.pl
new file mode 100644
index 0000000000..9198eecce5
--- /dev/null
+++ b/challenge-144/lubos-kolouch/perl/ch-1.pl
@@ -0,0 +1,27 @@
+use strict;
+use warnings;
+
+sub is_prime {
+    my ($n) = @_;
+    return 0 if $n < 2;
+    for my $i ( 2 .. sqrt $n ) {
+        return 0 if $n % $i == 0;
+    }
+    return 1;
+}
+
+sub generate_semiprimes {
+    my ($n) = @_;
+    my @primes = grep { is_prime($_) } ( 2 .. $n );
+    my %semiprimes;
+
+    for my $i ( 0 .. $#primes ) {
+        for my $j ( $i .. $#primes ) {
+            my $semiprime = $primes[$i] * $primes[$j];
+            $semiprimes{$semiprime} = 1 if $semiprime <= $n;
+        }
+    }
+    return sort { $a <=> $b } keys %semiprimes;
+}
+
+print join ", ", generate_semiprimes(100);
diff --git a/challenge-144/lubos-kolouch/perl/ch-2.pl b/challenge-144/lubos-kolouch/perl/ch-2.pl
new file mode 100644
index 0000000000..bbb813a1bf
--- /dev/null
+++ b/challenge-144/lubos-kolouch/perl/ch-2.pl
@@ -0,0 +1,24 @@
+use strict;
+use warnings;
+
+sub ulam_sequence {
+    my ( $u, $v, $n ) = @_;
+    $n //= 10;
+    my @sequence = ( $u, $v );
+    while ( @sequence < $n ) {
+        my %sums;
+        for my $i ( 0 .. $#sequence ) {
+            for my $j ( $i + 1 .. $#sequence ) {
+                $sums{ $sequence[$i] + $sequence[$j] }++;
+            }
+        }
+        my $next_val = ( sort { $a <=> $b }
+              grep { $sums{$_} == 1 and $_ > $sequence[-1] } keys %sums )[0];
+        push @sequence, $next_val;
+    }
+    return @sequence;
+}
+
+print join( ", ", ulam_sequence( 1, 2 ) ), "\n";
+print join( ", ", ulam_sequence( 2, 3 ) ), "\n";
+print join( ", ", ulam_sequence( 2, 5 ) ), "\n";
diff --git a/challenge-144/lubos-kolouch/python/ch-1.py b/challenge-144/lubos-kolouch/python/ch-1.py
new file mode 100644
index 0000000000..96562b361f
--- /dev/null
+++ b/challenge-144/lubos-kolouch/python/ch-1.py
@@ -0,0 +1,27 @@
+#!/usr/bin/env python
+# -*- coding: utf-8 -*-
+
+
+def is_prime(n):
+    if n < 2:
+        return False
+    for i in range(2, int(n**0.5) + 1):
+        if n % i == 0:
+            return False
+    return True
+
+
+def generate_semiprimes(n):
+    primes = [i for i in range(2, n + 1) if is_prime(i)]
+    semiprimes = set()
+
+    for i in range(len(primes)):
+        for j in range(i, len(primes)):
+            semiprime = primes[i] * primes[j]
+            if semiprime <= n:
+                semiprimes.add(semiprime)
+
+    return sorted(list(semiprimes))
+
+
+print(generate_semiprimes(100))
diff --git a/challenge-144/lubos-kolouch/python/ch-2.py b/challenge-144/lubos-kolouch/python/ch-2.py
new file mode 100644
index 0000000000..a27d2b676e
--- /dev/null
+++ b/challenge-144/lubos-kolouch/python/ch-2.py
@@ -0,0 +1,19 @@
+def ulam_sequence(u, v, n=10):
+    sequence = [u, v]
+    while len(sequence) < n:
+        sums = {
+            sequence[i] + sequence[j]: 0
+            for i in range(len(sequence))
+            for j in range(i + 1, len(sequence))
+        }
+        for i in range(len(sequence)):
+            for j in range(i + 1, len(sequence)):
+                sums[sequence[i] + sequence[j]] += 1
+        next_val = min(x for x in sums if sums[x] == 1 and x > sequence[-1])
+        sequence.append(next_val)
+    return sequence
+
+
+print(ulam_sequence(1, 2))
+print(ulam_sequence(2, 3))
+print(ulam_sequence(2, 5))
diff --git a/challenge-145/lubos-kolouch/perl/ch-1.pl b/challenge-145/lubos-kolouch/perl/ch-1.pl
new file mode 100644
index 0000000000..927bca97b6
--- /dev/null
+++ b/challenge-145/lubos-kolouch/perl/ch-1.pl
@@ -0,0 +1,15 @@
+use strict;
+use warnings;
+
+sub dot_product {
+    my ( $a, $b ) = @_;
+    my $dot_product = 0;
+    for my $i ( 0 .. $#$a ) {
+        $dot_product += $a->[$i] * $b->[$i];
+    }
+    return $dot_product;
+}
+
+my @a = ( 1, 2, 3 );
+my @b = ( 4, 5, 6 );
+print dot_product( \@a, \@b );    # Output: 32
diff --git a/challenge-145/lubos-kolouch/perl/ch-2.pl b/challenge-145/lubos-kolouch/perl/ch-2.pl
new file mode 100644
index 0000000000..a148ba5490
--- /dev/null
+++ b/challenge-145/lubos-kolouch/perl/ch-2.pl
@@ -0,0 +1,23 @@
+use strict;
+use warnings;
+
+sub palindromic_tree {
+    my ($s) = @_;
+    my @result;
+    for my $i ( 0 .. length($s) - 1 ) {
+        for my $j ( $i + 1 .. length($s) ) {
+            my $substring = substr $s, $i, $j - $i;
+            if ( $substring eq reverse $substring ) {
+                push @result, $substring;
+            }
+        }
+    }
+    return \@result;
+}
+
+my $s = 'redivider';
+print join( " ", @{ palindromic_tree($s) } ),
+  "\n";    # Output: r redivider e edivide d divid i ivi v
+
+$s = 'deific';
+print join( " ", @{ palindromic_tree($s) } ), "\n";    # Output: d e i ifi f c
diff --git a/challenge-145/lubos-kolouch/python/ch-1.py b/challenge-145/lubos-kolouch/python/ch-1.py
new file mode 100644
index 0000000000..bcd2e57de6
--- /dev/null
+++ b/challenge-145/lubos-kolouch/python/ch-1.py
@@ -0,0 +1,11 @@
+#!/usr/bin/env python
+# -*- coding: utf-8 -*-
+
+
+def dot_product(a, b):
+    return sum(x * y for x, y in zip(a, b))
+
+
+a = [1, 2, 3]
+b = [4, 5, 6]
+print(dot_product(a, b))  # Output: 32
diff --git a/challenge-145/lubos-kolouch/python/ch-2.py b/challenge-145/lubos-kolouch/python/ch-2.py
new file mode 100644
index 0000000000..7a9584b223
--- /dev/null
+++ b/challenge-145/lubos-kolouch/python/ch-2.py
@@ -0,0 +1,21 @@
+#!/usr/bin/env python
+# -*- coding: utf-8 -*-
+
+
+def palindromic_tree(s):
+    result = []
+    for i in range(len(s)):
+        for j in range(i + 1, len(s) + 1):
+            substring = s[i:j]
+            if substring == substring[::-1]:
+                result.append(substring)
+    return result
+
+
+s = "redivider"
+print(
+    palindromic_tree(s)
+)  # Output: ['r', 'redivider', 'e', 'edivide', 'd', 'divid', 'i', 'ivi', 'v']
+
+s = "deific"
+print(palindromic_tree(s))  # Output: ['d', 'e', 'i', 'ifi', 'f', 'c']
diff --git a/challenge-146/lubos-kolouch/perl/ch-1.pl b/challenge-146/lubos-kolouch/perl/ch-1.pl
new file mode 100644
index 0000000000..c14852dffa
--- /dev/null
+++ b/challenge-146/lubos-kolouch/perl/ch-1.pl
@@ -0,0 +1,17 @@
+use strict;
+use warnings;
+
+sub nth_prime {
+    my ($n)    = @_;
+    my @primes = (2);
+    my $i      = 3;
+    while ( @primes < $n ) {
+        if ( !grep { $i % $_ == 0 } @primes ) {
+            push @primes, $i;
+        }
+        $i += 2;
+    }
+    return $primes[-1];
+}
+
+print nth_prime(10001), "\n";    # Output: 104743
diff --git a/challenge-146/lubos-kolouch/perl/ch-2.pl b/challenge-146/lubos-kolouch/perl/ch-2.pl
new file mode 100644
index 0000000000..3537ebcfc9
--- /dev/null
+++ b/challenge-146/lubos-kolouch/perl/ch-2.pl
@@ -0,0 +1,22 @@
+use strict;
+use warnings;
+use Math::Fraction;
+
+sub find_ancestors {
+    my ($fraction) = @_;
+    my ( $num, $denom ) = split( '/', $fraction );
+    my $parent =
+      $denom > $num
+      ? Math::Fraction->new( $num,          $denom - $num )
+      : Math::Fraction->new( $num - $denom, $denom );
+    my $grandparent =
+      $parent->denominator > $parent->numerator
+      ? Math::Fraction->new( $parent->numerator,
+        $parent->denominator - $parent->numerator )
+      : Math::Fraction->new( $parent->numerator - $parent->denominator,
+        $parent->denominator );
+    return $parent->to_string, $grandparent->to_string;
+}
+
+print join( ' and ', find_ancestors('3/5') ), "\n";    # Output: 3/2 and 1/2
+print join( ' and ', find_ancestors('4/3') ), "\n";    # Output: 1/3 and 1/2
diff --git a/challenge-146/lubos-kolouch/python/ch-1.py b/challenge-146/lubos-kolouch/python/ch-1.py
new file mode 100644
index 0000000000..3191b3e2e4
--- /dev/null
+++ b/challenge-146/lubos-kolouch/python/ch-1.py
@@ -0,0 +1,15 @@
+#!/usr/bin/env python
+# -*- coding: utf-8 -*-
+
+
+def nth_prime(n):
+    primes = [2]
+    i = 3
+    while len(primes) < n:
+        if all(i % p > 0 for p in primes):
+            primes.append(i)
+        i += 2
+    return primes[-1]
+
+
+print(nth_prime(10001))  # Output: 104743
diff --git a/challenge-146/lubos-kolouch/python/ch-2.py b/challenge-146/lubos-kolouch/python/ch-2.py
new file mode 100644
index 0000000000..0cfdb31445
--- /dev/null
+++ b/challenge-146/lubos-kolouch/python/ch-2.py
@@ -0,0 +1,19 @@
+#!/usr/bin/env python
+# -*- coding: utf-8 -*-
+
+from fractions import Fraction
+
+
+def find_ancestors(fraction):
+    num, denom = map(int, fraction.split("/"))
+    parent = Fraction(num, denom - num) if denom > num else Fraction(num - denom, denom)
+    grandparent = (
+        Fraction(parent.numerator, parent.denominator - parent.numerator)
+        if parent.denominator > parent.numerator
+        else Fraction(parent.numerator - parent.denominator, parent.denominator)
+    )
+    return str(parent), str(grandparent)
+
+
+print(find_ancestors("3/5"))  # Output: ('3/2', '1/2')
+print(find_ancestors("4/3"))  # Output: ('1/3', '1/2')