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1 files changed, 35 insertions, 0 deletions

diff --git a/racket/leetcode/lc-2-add-two-numbers.rkt b/racket/leetcode/lc-2-add-two-numbers.rkt
new file mode 100644
index 0000000..8062817
--- /dev/null
+++ b/racket/leetcode/lc-2-add-two-numbers.rkt
@@ -0,0 +1,35 @@
+#lang racket
+; Definition for singly-linked list:
+
+
+; val : integer?
+; next : (or/c list-node? #f)
+(struct list-node
+  (val next) #:mutable #:transparent)
+
+; constructor
+(define (make-list-node val [next-node #f])
+  (list-node val next-node))
+
+
+(define/contract (add-two-numbers l1 l2)
+  (-> (or/c list-node? #f) (or/c list-node? #f) (or/c list-node? #f))
+  (define (process-list node [acc '()])
+    (if (list-node-next node)
+        (process-list (list-node-next node) (cons (list-node-val node) acc))
+        (cons (list-node-val node) acc)))
+  (define sum-of-lists (+ (string->number (apply ~a (process-list l1)))
+                          (string->number (apply ~a (process-list l2)))))
+  (define sum-list-digits
+    (reverse
+     (map (λ (x) (string->number (string x)))
+          (string->list (number->string sum-of-lists)))))
+  (define (build-list l)
+    (if (empty? l)
+        #f
+        (make-list-node (car l) (build-list (cdr l)))))
+  (build-list sum-list-digits))
+
+(define list1 (make-list-node 2 (make-list-node 4 (make-list-node 3))))
+(define list2 (make-list-node 5 (make-list-node 6 (make-list-node 4))))
+(add-two-numbers list1 list2)
\ No newline at end of file