Maximum triangle path sum: Difference between revisions

=={{header|Common Lisp}}==

<lang lisp>(defun find-max-path-sum (s)

(let ((triangle (loop for line = (read-line s NIL NIL)

while line

collect (with-input-from-string (str line)

(loop for n = (read str NIL NIL)

while n

collect n)))))

(flet ((get-max-of-pairs (xs)

(maplist (lambda (ys)

(and (cdr ys) (max (car ys) (cadr ys))))

xs)))

(car (reduce (lambda (xs ys)

(mapcar #'+ (get-max-of-pairs xs) ys))

(reverse triangle))))))

(defparameter *small-triangle*

" 55

94 48

95 30 96

77 71 26 67")

(format T "~a~%" (with-input-from-string (s *small-triangle*)

(find-max-path-sum s)))

(format T "~a~%" (with-open-file (f "triangle.txt")

(find-max-path-sum f)))</lang>

{{Out}}

<pre>321

1320</pre>