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(defun shiritori (num-words)
  (loop
     with ht = (make-hash-table :size num-words :test 'equal)
     repeat (1- num-words)
     for player = 1 then (- 1 player)
     for prev-word = (read-line) then curr-word
     for curr-word = (read-line) then (read-line)
     do
       (setf (gethash prev-word ht) t)
       (when (or (char/= (char curr-word 0) (char prev-word (1- (length prev-word))))
                 (gethash curr-word ht))
         (return player))))

(defun main ()
  (case (shiritori (read))
    (0 (format t "Player 1 lost"))
    (1 (format t "Player 2 lost"))
    (otherwise (format t "Fair Game"))))

(main)

#|
UPDATE: I generated a torture test data-set to profile the code. Just 100,000 random
"words" of length 120 (the problem's declared input constraints)such that the first
letter of i-th word equals the last letter of the (i-1)-th word (i.e. a "Fair Game").

The culprit is READ-LINE.

GET-HASH and PUT-HASH just wrap (GETHASH CURR-WORD HT) and (SETF (GETHASH PREV-WORD HT) T),
respectively.

seconds  |     gc     |    consed   |  calls  |  sec/call  |  name ;
----------------------------------------------------------- ;
1.421 |      0.034 | 102,398,912 | 100,000 |   0.000014 | READ-LINE ;
0.076 |      0.000 |           0 |  99,999 |   0.000001 | PUT-HASH ;
0.071 |      0.000 |           0 |  99,999 |   0.000001 | GET-HASH ;
----------------------------------------------------------- ;
1.567 |      0.034 | 102,398,912 | 299,998 |            | Total ;

BACKGROUND 
==========
See: <https://open.kattis.com/problems/shiritori>, click on statistics.
Common Lisp (SBCL) has the slowest solution (namely, mine, the one shown above.)
The equivalent C++ sol'n, for example, literally translated from Lisp to C++ using
unordered_map instead of make-hash-table, takes 0.06s.
|#

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