Max Consecutive Sum (problem of the week on http://codingforinterviews.com)

gistfile1.lisp

(defun max_consecutive_sum (arr)
  (let ((max_ending_here 0) (max_so_far 0))
    (dotimes (x (length arr))
      (setf max_ending_here (max 0 (+ (aref arr x) max_ending_here)))
      (setf max_so_far (max max_so_far max_ending_here)))
    max_so_far))

(format t "~S~%" (max_consecutive_sum #(-1 5 6 -2 20 -50 4))) ; 29
(format t "~S~%" (max_consecutive_sum #(-2 1 -3 4 -1 2 1 -5 4))) ; 6