[leetcode] 110. 平衡二叉树
实际上递归的求每一个左右子树的最大深度即可,如果差值大于1,返回一个-1的状态上去
class Solution {
public boolean isBalanced(TreeNode root) {
return depth(root)!=-1;
}
public int depth(TreeNode root) {
if (null == root) return 0;
int left = depth(root.left);
int right = depth(root.right);
if (left != -1 && right != -1 && Math.abs(left - right) <= 1) {
return Math.max(left, right) + 1;
} else {
return -1;
}
}
}