blob: b01e3bb90c36f7c861b59a9fe3fbf51b81bc988a (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
|
#lang racket
(define word-filter%
(class object%
(super-new)
; words : (listof string?)
(init-field
words) ; Take in the provided dictionary.
(define word-ends-hash (make-hash)) ; Make an empty hash table.
(for/list ([w (in-list words)] ; For each word in the dictionary,
[index (in-naturals)]) ; and its corresponding index,
(define len (string-length w)) ; calculate its length,
(for*/list ([head (in-range 1 (min 11 (add1 len)))] ; and for every combination of head length
[tail (in-range 1 (min 11 (add1 len)))]) ; and tail length
(hash-set! word-ends-hash ; from 1 to the max. affix length,
(list (substring w 0 head) ; set the key to the list containing
(substring w (- len tail) len)) ; the prefix and suffix
index))) ; and map it to the word's index.
; f : string? string? -> exact-integer?
(define/public (f prefix suffix) ; Return the mapped value for the affixes
(hash-ref word-ends-hash (list prefix suffix) -1)))) ; or -1 if it doesn't exist.
;; Your word-filter% object will be instantiated and called as such:
;; (define obj (new word-filter% [words words]))
;; (define param_1 (send obj f prefix suffix))
|
