From 6f98e0d38fbb3d282a627ba70ddeb9977815bb4c Mon Sep 17 00:00:00 2001
From: bd <bdunahu@operationnull.com>
Date: Sun, 9 Jun 2024 17:10:45 -0600
Subject: Implementation and tests for "combinations" function

---
 combinations/combinations.scm | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)
 create mode 100644 combinations/combinations.scm

(limited to 'combinations/combinations.scm')

diff --git a/combinations/combinations.scm b/combinations/combinations.scm
new file mode 100644
index 0000000..8817176
--- /dev/null
+++ b/combinations/combinations.scm
@@ -0,0 +1,19 @@
+(define-module (combinations)
+  #:export (combinations))
+
+
+(define (combinations lst n)
+  "Return N length subsequences of elements from
+LST."
+  (if (or (null? lst) (zero? n))
+      (if (zero? n)'(()) '())
+      (let loop ((lst lst) (result '()))
+        (if (null? lst)
+            result
+            (let ((next-lst (cdr lst)))
+	      (loop next-lst
+                    (append result
+                            (map (lambda (combo)
+                                   (cons (car lst) combo))
+                                 (combinations next-lst
+					       (1- n))))))))))
-- 
cgit v1.2.3