Merge remote-tracking branch 'upstream/master'

# Conflicts:
#	challenge-160/paulo-custodio/Makefile

2 files changed, 40 insertions, 0 deletions

diff --git a/challenge-159/lubos-kolouch/python/ch-1.py b/challenge-159/lubos-kolouch/python/ch-1.py
new file mode 100644
index 0000000000..cdfcf94d85
--- /dev/null
+++ b/challenge-159/lubos-kolouch/python/ch-1.py
@@ -0,0 +1,20 @@
+""" Challenge 159 Task 1"""
+
+
+def farey_sequence(n: int, descending: bool = False) -> str:
+    """Print the n'th Farey sequence. Allow for either ascending or descending."""
+    (a, b, c, d) = (0, 1, 1, n)
+
+    solution = []
+    if descending:
+        (a, c) = (1, n - 1)
+    solution.append(f"{a}/{b}")
+    while (c <= n and not descending) or (a > 0 and descending):
+        k = (n + b) // d
+        (a, b, c, d) = (c, d, k * c - a, k * d - b)
+        solution.append(f"{a}/{b}")
+
+    return ", ".join(solution)
+
+
+assert farey_sequence(5) == "0/1, 1/5, 1/4, 1/3, 2/5, 1/2, 3/5, 2/3, 3/4, 4/5, 1/1"
diff --git a/challenge-159/lubos-kolouch/python/ch-2.py b/challenge-159/lubos-kolouch/python/ch-2.py
new file mode 100644
index 0000000000..b5ab8e6d88
--- /dev/null
+++ b/challenge-159/lubos-kolouch/python/ch-2.py
@@ -0,0 +1,20 @@
+""" Challenge 159 Task 2"""
+from sympy.ntheory import factorint
+
+
+def get_moebius_nr(what: int):
+    """Get the moebius nr"""
+    factors = factorint(what)
+
+    if any(value > 1 for value in factors.values()):
+        return 0
+
+    if len(factors) % 2 == 0:
+        return 1
+
+    return -1
+
+
+assert get_moebius_nr(5) == -1
+assert get_moebius_nr(10) == 1
+assert get_moebius_nr(20) == 0