Given a binary tree, determine if it is height-balanced.
For this problem, a height-balanced binary tree is defined as a binary tree in which the depth of the two subtrees of every node never differ by more than 1.
左子树本身平衡＋右子数本身平衡＋左子树与右子数最大深度差小于1
def is_balanced(root) return true if not root is_balanced(root.left) and is_balanced(root.right) and (max_depth(root.left) - max_depth(root.right)).abs <= 1 end def max_depth(root) root ? [max_depth(root.left),max_depth(root.right)].max + 1 : 0 end
Leetcode 110 Balanced Binary Tree
原文：http://www.cnblogs.com/lilixu/p/4575177.html