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.
题目含义：题意为判断一颗树是否为平衡二叉树。（PS：平衡二叉树的特性：它是一棵空树或它的左右两个子树的高度差的绝对值不超过1，并且左右两个子树都是一棵平衡二叉树）
1 private int getDepth(TreeNode root) { 2 if (root == null) return 0; 3 return 1 + Math.max(getDepth(root.left), getDepth(root.right)); 4 } 5 6 public boolean isBalanced(TreeNode root) { 7 if (root == null) return true; 8 if (Math.abs(getDepth(root.left) - getDepth(root.right)) > 1) return false; 9 return isBalanced(root.left) && isBalanced(root.right); 10 }
原文：http://www.cnblogs.com/wzj4858/p/7707166.html