adding old leetcode solutions

1 files changed, 23 insertions, 0 deletions

diff --git a/leetcode/lc-500-keyboard-row.rkt b/leetcode/lc-500-keyboard-row.rkt
new file mode 100644
index 0000000..5f13143
--- /dev/null
+++ b/leetcode/lc-500-keyboard-row.rkt
@@ -0,0 +1,23 @@
+#lang racket
+
+(define keyboard-rows (list "qwertyuiop" 
+                            "asdfghjkl" 
+                            "zxcvbnm"))
+
+(define keyboard-row-sets
+  (for/list ([row keyboard-rows])
+    (list->set (map string (string->list row)))))
+
+(define/contract (find-words words)
+  (-> (listof string?) (listof string?))
+  (define word-checks
+    (for/list ([w words])
+      (define word-set
+        (list->set (map string (string->list (string-downcase w)))))
+      (if (for/or ([row keyboard-row-sets])
+            (subset? word-set row))
+          w
+          '())))
+  (filter-not empty? word-checks))
+
+(find-words '("Hello" "Alaska" "Dad" "Peace"))
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