T26.java

package web; /**
 * @program LeetNiu
 * @description: 二叉搜索树与双向链表
 * @author: mf
 * @create: 2020/01/13 13:42
 */

/**
 * 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。
 */
public class T26 {
    public TreeNode Convert(TreeNode pRootOfTree) {
        if (pRootOfTree == null) return null;
        if (pRootOfTree.left == null && pRootOfTree.right == null) return pRootOfTree;
        TreeNode left = Convert(pRootOfTree.left);
        TreeNode p = left;
        while (p != null && p.right != null) {
            p = p.right;
        }
        if (left != null) {
            p.right = pRootOfTree;
            pRootOfTree.left = p;
        }
        TreeNode right = Convert(pRootOfTree.right);
        if (right != null) {
            pRootOfTree.right = right;
            right.left = pRootOfTree;
        }
        return left != null ? left : pRootOfTree;
    }
}