From fafbeaf9e3c09ba7a5bea7e47d5736001f8a5aa1 Mon Sep 17 00:00:00 2001
From: HJ <thechairman@thechairman.info>
Date: Tue, 17 Jan 2023 12:46:04 -0500
Subject: adding old leetcode solutions

---
 leetcode/lc-217-contains-duplicate.rkt | 12 ++++++++++++
 1 file changed, 12 insertions(+)
 create mode 100644 leetcode/lc-217-contains-duplicate.rkt

(limited to 'leetcode/lc-217-contains-duplicate.rkt')

diff --git a/leetcode/lc-217-contains-duplicate.rkt b/leetcode/lc-217-contains-duplicate.rkt
new file mode 100644
index 0000000..ca8d193
--- /dev/null
+++ b/leetcode/lc-217-contains-duplicate.rkt
@@ -0,0 +1,12 @@
+#lang racket
+(define/contract (contains-duplicate nums)
+  (-> (listof exact-integer?) boolean?)
+  (define nums-hash (make-hash))
+  (define (check-next-number nums)
+    (cond [(empty? nums) #false]
+          [(hash-ref nums-hash (car nums) #false) #true]
+          [else (hash-set! nums-hash (car nums) #true)
+                (check-next-number (cdr nums))]))
+  (check-next-number nums))
+
+(contains-duplicate '(1 2 3))
\ No newline at end of file
-- 
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