adding old leetcode solutions

1 files changed, 23 insertions, 0 deletions

diff --git a/leetcode/lc-290-word-pattern.rkt b/leetcode/lc-290-word-pattern.rkt
new file mode 100644
index 0000000..77cdba0
--- /dev/null
+++ b/leetcode/lc-290-word-pattern.rkt
@@ -0,0 +1,23 @@
+#lang racket
+(define match-string "abba")
+(define a "dog")
+(define b "cat")
+(define Σ "dog cat cat dog")
+
+(define/contract (word-pattern pattern s)
+  (-> string? string? boolean?)
+  (define pattern-list (map string (string->list pattern)))
+  (define s-list (string-split s))
+  (define match-hash (make-hash))
+  (if (= (length pattern-list) (length s-list))
+      (for/and ([pattern-part pattern-list]
+                [s-part s-list])
+        (cond [(and (not (hash-has-key? match-hash pattern-part))
+                    (member s-part (hash-values match-hash))) #f]
+              [(not (hash-has-key? match-hash pattern-part))
+               (hash-set! match-hash pattern-part s-part) #t] 
+              [(string=? (hash-ref match-hash pattern-part) s-part) #t]
+              [else #f]))
+      #f))
+
+(word-pattern match-string Σ) 
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