1 files changed, 14 insertions, 0 deletions
diff --git a/leetcode/lc-819-most-common-word.rkt b/leetcode/lc-819-most-common-word.rkt
new file mode 100644
index 0000000..68a89c3
--- /dev/null
+++ b/leetcode/lc-819-most-common-word.rkt
@@ -0,0 +1,14 @@
+#lang racket
+(define/contract (most-common-word paragraph banned)
+  (-> string? (listof string?) string?)
+  (define word-count-hash (make-hash))
+  (define banned-word-hash
+    (apply hash (flatten (map (λ (w) (cons w 'banned)) banned))))
+  (define word-list
+    ((compose string-split string-downcase)
+     (string-replace paragraph #px"[^A-Za-z[:space:]]" " ")))
+  (for/list ([word (in-list word-list)])
+    (cond [(hash-has-key? banned-word-hash word) void]
+          [else (hash-update! word-count-hash word add1 0)]))
+  (car (argmax cdr (hash->list word-count-hash))))
+