Personal tools

99 questions/Solutions/61

From HaskellWiki

Jump to: navigation, search

Count the leaves of a binary tree

A leaf is a node with no successors. Write a predicate count_leaves/2 to count them.

countLeaves Empty                  = 0
countLeaves (Branch _ Empty Empty) = 1
countLeaves (Branch _ l r)         = countLeaves l + countLeaves r