; reluctant search
 
(define (research x xs i j)
    (if (> i j)
        -1
        (if (= i j)
            (if (= x (vector-ref xs i))
                i
                -1)
            (let ((m (quotient (+ i j) 2)))
                (if (<= x (vector-ref xs m))
                    (let ((k (research x xs (+ m 1) j)))
                        (if (= k -1)
                            (research x xs i m)
                            k)))
                    (let ((k (research x xs i m)))
                        (if (= k -1)
                            (research x xs (+ m 1) j)
                            k))))))
 
(display (research 3 '#(1 2 3 5 6) 0 4)) (newline)
(display (research 4 '#(1 2 3 5 6) 0 4)) (newline); your code goes here

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