Clean up and get ready for two sum assignment

misc/birthday_problem.py

@@ -0,0 +1,16 @@
+def p_all_different(n):
+    p = 1
+    free_days = 365
+    days_year = 365
+    for i in range(0, n):
+        p = p * (free_days / days_year)
+        free_days -= 1
+    return p
+
+
+if __name__ == "__main__":
+    for i in range(1, 30):
+        print(f"p_all_different({i})={p_all_different(i)}")
+        if  p_all_different(i) < 0.5:
+            break
+