(define qsortPartition (lambda (pivot L L1 L2) (if (null? L) (cons L1 L2) ; return L1 and L2 once L is exhausted (let ((firstElement (car L))) (if (< firstElement pivot) ; add head of L to L1 and partition rest of L (qsortPartition pivot (cdr L) (cons firstElement L1) L2) ; add head of L to L2 and partition rest of L (qsortPartition pivot (cdr L) L1 (cons firstElement L2))))))) (define qsort (lambda (L) (if (null? L) L (let* ((result (qsortPartition (car L) (cdr L) '() '())) (lesserList (car result)) (greaterList (cdr result))) (append (qsort lesserList) (list (car L)) (qsort greaterList)))))) (define qsortPartition (lambda (pivot L) (if (null? L) (cons '() '()) (let* ((result (qsortPartition pivot (cdr L))) (lesserList (car result)) (greaterList (cdr result))) (if (< (car L) pivot) (cons (cons (car L) lesserList) greaterList) (cons lesserList (cons (car L) greaterList)))))))