Given a singly linked list where elements are sorted in ascending order, convert it to a height balanced BST.
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.
Example：
Given the sorted linked list: [-10,-3,0,5,9],One possible answer is: [0,-3,9,-10,null,5]
解释下题目：
跟之前的108其实是一样的
1. 二分法递归做
实际耗时：2ms
public TreeNode sortedListToBST(ListNode head) {
List<Integer> res = new ArrayList<>();
ListNode cur = head;
while (cur != null) {
res.add(cur.val);
cur = cur.next;
}
return recursive(res, 0, res.size() - 1);
}
public TreeNode recursive(List<Integer> res, int low, int high) {
if (low > high) {
return null;
}
int mid = (low + high) >> 1;
TreeNode root = new TreeNode(res.get(mid));
root.left = recursive(res, low, mid - 1);
root.right = recursive(res, mid + 1, high);
return root;
}
踩过的坑：
思路见108
