From 1eefd58ca4fdb5d2f51f657bfd70c9a89a4707db Mon Sep 17 00:00:00 2001
From: Iru Cai <mytbk920423@gmail.com>
Date: Thu, 24 May 2018 21:39:58 +0800
Subject: initial commit

---
 euler4.scm | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)
 create mode 100644 euler4.scm

(limited to 'euler4.scm')

diff --git a/euler4.scm b/euler4.scm
new file mode 100644
index 0000000..09408a9
--- /dev/null
+++ b/euler4.scm
@@ -0,0 +1,20 @@
+(define (palindrome? x)
+  (define (rev x ans)
+	(if (= x 0)
+	  ans
+	  (let ((r (remainder x 10)))
+	   (rev (/ (- x r) 10) (+ r (* ans 10))))))
+  (= (rev x 0) x))
+
+(define (bigpal ans x y)
+ (if (> x 999)
+  ans
+  (if (> y 999)
+   (bigpal ans (+ x 1) (+ x 1))
+   (if (and (palindrome? (* x y)) (> (* x y) ans))
+	(bigpal (* x y) x (+ y 1))
+	(bigpal ans x (+ y 1))))))
+
+(display (bigpal 0 100 100))
+(newline)
+
-- 
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