From 7540db381bd0a163cd28c02a679aaefcea62bf0b Mon Sep 17 00:00:00 2001
From: Ryan Martin <51780559+rmrt1n@users.noreply.github.com>
Date: Mon, 25 Oct 2021 20:30:08 +0800
Subject: [PATCH] added code for binomial coefficient

---
 algorithms/math/binomial-coefficient.rkt | 9 +++++++++
 1 file changed, 9 insertions(+)
 create mode 100644 algorithms/math/binomial-coefficient.rkt

diff --git a/algorithms/math/binomial-coefficient.rkt b/algorithms/math/binomial-coefficient.rkt
new file mode 100644
index 0000000..e28b2a2
--- /dev/null
+++ b/algorithms/math/binomial-coefficient.rkt
@@ -0,0 +1,9 @@
+#lang racket
+
+(provide binomial)
+
+(define (binomial n k)
+  (let ([fac (lambda (n)
+               (let loop ([acc 1] [n n])
+                 (if (zero? n) acc (loop (* acc n) (sub1 n)))))])
+    (/ (fac n) (fac k) (fac (- n k)))))