#lang debug racket
(require racket/dict)
(provide (all-defined-out))

(define letter-scores
  '((A 4 4)
    (B 1 3)
    (C 2 3)
    (D 1 2)
    (E 1 3)
    (F 1 3)
    (G 2 3)
    (H 1 1)
    (I 1 1)
    (J 3 1)
    (K 1 3)
    (L 1 4)
    (M 1 1)
    (N 1 1)
    (O 2 2)
    (P 1 3)
    (Q 2 2)
    (R 1 3)
    (S 3 3)
    (T 4 4)
    (U 1 1)
    (V 4 4)
    (W 4 4)
    (X 3 3)
    (Y 4 4)
    (Z 3 3)
    (a 3 3)
    (b 1 2)
    (c 2 3)
    (d 2 1)
    (e 2 3)
    (f 3 3)
    (g 3 3)
    (h 1 1)
    (i 1.5 1.5)
    (j 3 1)
    (k 1 3)
    (l 1.5 1.5)
    (m 1 1)
    (n 1 1)
    (o 2 2)
    (p 1 2)
    (q 2 1)
    (r 1 3)
    (s 3 3)
    (t 3 3)
    (u 1 1)
    (v 4 4)
    (w 4 4)
    (x 3 3)
    (y 4 4)
    (z 3 3)))

(define left-score-table
  (for/hasheqv ([(letter scores) (in-dict letter-scores)])
    (values (car (string->list (symbol->string letter))) (car scores))))

(define right-score-table
  (for/hasheqv ([(letter scores) (in-dict letter-scores)])
    (values (car (string->list (symbol->string letter))) (cadr scores))))


(define (kernscore word)
  (define cs (string->list word))
  (/ (for/sum ([left-c (in-list cs)]
               [right-c (in-list (cdr cs))])
       (* (hash-ref right-score-table left-c)
          (hash-ref left-score-table right-c)))
     (length cs)))