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二叉搜索树与双向链表

admin 11月 14, 2020 0

题目描述

输入一棵二叉搜索树，将该二叉搜索树转换成一个排序的双向链表。要求不能创建任何新的结点，只能调整树中结点指针的指向。

我的解答

/**
public class TreeNode {
    int val = 0;
    TreeNode left = null;
    TreeNode right = null;

    public TreeNode(int val) {
        this.val = val;

    }

}
*/
public class Solution {
    TreeNode cur = null;
    TreeNode head = null;
    public TreeNode Convert(TreeNode pRootOfTree) {
        if (null == pRootOfTree) {
            return null;
        } else {
            TreeNode prev = null;
            midVisit(pRootOfTree);
            while (null != pRootOfTree.left) {
                pRootOfTree = pRootOfTree.left;
            }
            return pRootOfTree;
        }
    }
    
    private void midVisit(TreeNode next){
        if (null == next) {
            return;
        }
        midVisit(next.left);
        if (null == head) {
            cur = next;
            head = next;
        } else {
            cur.right = next;
            next.left = cur;
            cur = next;
        }
        midVisit(next.right);
    }
}