exercises

1 files changed, 29 insertions, 0 deletions

diff --git a/rosetta/factors-of-int.neb b/rosetta/factors-of-int.neb
new file mode 100644
index 0000000..ea3ca15
--- /dev/null
+++ b/rosetta/factors-of-int.neb
@@ -0,0 +1,29 @@
+(func .list-of-num (num)
+    (def nums (list))
+    (for-count num
+        (redef nums (append nums _idx_)))
+    nums)
+
+(func .rough-sqrt (num) (.rough-sqrt num 1))
+
+(func .rough-sqrt (num val)
+    (branch
+        ((eq? (* val val) num) val)
+        ((> (* val val) num) (- val 1))
+        (#true
+            (.rough-sqrt num (+ 1 val)))))
+
+(func factor-naive (num)
+    (filter (lambda (x) (int? (/ num x))) (.list-of-num num)))
+
+(func factor-better (num)
+    (append
+        (filter (lambda (x) (int? (/ num x))) (.list-of-num (floor (/ num 2))))
+        num))
+
+(func factor-even-better (num)
+    (def ret (list))
+    (for-each (.list-of-num (.rough-sqrt num))
+        (if (int? (/ num _item_))
+            (redef ret (append ret (list _item_ (/ num _item_))))))
+    ret)