https://leetcode-cn.com/problems/balanced-binary-tree/
image.png
（图片来源https://leetcode-cn.com/problems/balanced-binary-tree/
）
| 日期 | 是否一次通过 | comment |
|---|---|---|
| 2020-03-15 | 0 |
递归
public boolean isBalanced(TreeNode root) {
if(root == null) {
return true;
}
return helper(root) != -1;
}
private int helper(TreeNode root) {
if(root == null) {
return 0;
}
int leftD = helper(root.left);
int rightD = helper(root.right);
if(leftD == -1 || rightD == -1 || Math.abs(leftD-rightD) > 1) {
return -1;
}
return Math.max(leftD, rightD) + 1;
}
网友评论