- Added guest solutions by Laurent Rosenfeld.

2 files changed, 36 insertions, 0 deletions

diff --git a/challenge-175/laurent-rosenfeld/python/ch-1.py b/challenge-175/laurent-rosenfeld/python/ch-1.py
new file mode 100644
index 0000000000..78e40c3d33
--- /dev/null
+++ b/challenge-175/laurent-rosenfeld/python/ch-1.py
@@ -0,0 +1,23 @@
+from datetime import date,timedelta
+import sys
+
+def lastsundays (y):
+  for m in range(1,13):
+    if m == 12:
+      year = y + 1
+      month = 1
+    else:
+      year = y
+      month = m + 1
+
+    mthEnd = date(year, month, 1) - timedelta(days = 1)
+    weekDay = mthEnd.weekday()
+    lastSun = mthEnd - timedelta(days = (weekDay + 1) % 7)
+    print(lastSun)
+
+if len(sys.argv) == 2:
+  year = int(sys.argv[1])
+else:
+  year = 2022
+
+lastsundays(year)
diff --git a/challenge-175/laurent-rosenfeld/python/ch-2.py b/challenge-175/laurent-rosenfeld/python/ch-2.py
new file mode 100644
index 0000000000..d465124687
--- /dev/null
+++ b/challenge-175/laurent-rosenfeld/python/ch-2.py
@@ -0,0 +1,13 @@
+import math
+
+cache = [0] * 10000
+
+def is_perfect_totient (n):
+    tot = 0
+    for i in range(1, n):
+        if (math.gcd(n, i) == 1):
+            tot += 1
+
+​ sum = tot + cache[tot] ​ cache[n] = sum ​ return n == sum
+​
+i = 1 ​ count = 0 ​ while count < 20: ​ if isperfecttotient(i): ​ print(i, end = ” “) ​ count += 1 ​ i += 1 ​ print(” “)