Author: abaine Date: Sun Aug 19 17:22:39 2007 New Revision: 174

Added: trunk/funds/src/trees/utilities.lisp Log: Added tree-count and tree-count-if.

Added: trunk/funds/src/trees/utilities.lisp ============================================================================== --- (empty file) +++ trunk/funds/src/trees/utilities.lisp Sun Aug 19 17:22:39 2007 @@ -0,0 +1,18 @@ + +(in-package :funds) + +(defun tree-count (item tree &key (key #'bt-value) (test #'eql)) + "The number of sub-trees in the tree that satisfy the test." + (tree-count #'(lambda (x) + (funcall test x item)) + :key key)) + +(defun tree-count-if (predicate tree &key (key #'bt-value)) + "The number of sub-trees in the given tree that satisfy the test." + (if (tree-empty-p tree) + 0 + (+ (tree-count-if predicate (bt-left tree) :key key) + (funcall predicate (funcall key tree)) + (tree-count-if predicate (bt-right tree) :key key)))) + +