2 files changed, 0 insertions, 49 deletions
diff --git a/leetcode/1-two-sum/solution.rkt b/leetcode/1-two-sum/solution.rkt
deleted file mode 100644
index e155160..0000000
--- a/leetcode/1-two-sum/solution.rkt
+++ /dev/null
@@ -1,16 +0,0 @@
-#lang racket
-
-;; https://leetcode.com/problems/two-sum/description/
-
-(define/contract (two-sum nums target)
-  (-> (listof exact-integer?) exact-integer? (listof exact-integer?))
-  (define h (make-hash))
-  (define (loop nums index)
-    (define n (car nums))
-    (define diff (- target n))
-    (if (hash-has-key? h diff)
-        (list index (hash-ref h diff))
-        (let ()
-            (hash-set! h n index)
-            (loop (cdr nums) (+ 1 index)))))
-  (loop nums 0))
diff --git a/leetcode/20-valid-parentheses/solution.rkt b/leetcode/20-valid-parentheses/solution.rkt
deleted file mode 100644
index 559b90c..0000000
--- a/leetcode/20-valid-parentheses/solution.rkt
+++ /dev/null
@@ -1,33 +0,0 @@
-#lang racket
-
-;; https://leetcode.com/problems/valid-parentheses/
-
-(define (is-left-paren c)
-    (or (eq? c #\u28)
-        (eq? c #\[)
-        (eq? c #\{)))
-
-(define (right-paren c)
-    (cond ((eq? c #\u28) #\u29)
-          ((eq? c #\[) #\])
-          ((eq? c #\{) #\})))
-
-(define/contract (is-valid s)
-  (-> string? boolean?)
-  (define (loop s stack)
-    (if (= 0 (string-length s))
-        (null? stack)
-        (let ()
-            (define c (string-ref s 0))
-            (define remain (substring s 1))
-            (if (is-left-paren c)
-                (loop remain (cons c stack))
-                (if (null? stack)
-                    #f
-                    (let ()
-                        (define stack-top (car stack))
-                        (if (eq? c (right-paren stack-top))
-                            (loop remain (cdr stack))
-                            #f)))))))
-  (loop s '()))
-