LeetCode Convert Sorted List to Binary Search Tree（有序单链表转为平衡二叉树）

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题意：给出一个有序的单链表，将其转换成平衡二叉树

思路：因为是有序的，所以可以将其分成两部分，前部分作为左子树，后部分作为右子树

代码如下：

class ListNode{    int val;    ListNode next;    ListNode(int x) { val = x; }}class TreeNode{    int val;    TreeNode left;    TreeNode right;    TreeNode(int x) { val = x; }}class Solution{    public TreeNode sortedListToBST(ListNode head)    {        if (null == head) return null;        if (null == head.next)        {            return new TreeNode(head.val);        }        ListNode slow = head, fast = head.next.next;        while (fast != null && fast.next != null)        {            fast = fast.next.next;            slow = slow.next;        }        TreeNode node = new TreeNode(slow.next.val);        node.right = sortedListToBST(slow.next.next);        slow.next = null;        node.left = sortedListToBST(head);        return node;    }}

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