二叉搜索树转化为双向链表

最新推荐文章于 2021-05-20 18:10:45 发布

一只程序dog

最新推荐文章于 2021-05-20 18:10:45 发布

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分类专栏： Data Structure 文章标签：面试程序员面试金典

本文链接：https://blog.youkuaiyun.com/qq_29728627/article/details/53868681

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//使用双端队列，空间复杂度为O（N）

public TreeNode Convert(TreeNode pRootOfTree) {
        if (pRootOfTree == null) {
            return null;
        }
        ArrayDeque<TreeNode> ad = new ArrayDeque<TreeNode>();
        inOrder(pRootOfTree, ad);
        TreeNode head = ad.pop();
        head.left = null;
        TreeNode before = head;
        while (!ad.isEmpty()) {
            TreeNode tmp = ad.pop();
            tmp.left = before;
            before.right = tmp;
            before = tmp;
        }
        before.right = null;
        return head;
    }

    private void inOrder(TreeNode pRootOfTree, ArrayDeque<TreeNode> ad) {
        if (pRootOfTree == null) {
            return;
        }
        inOrder(pRootOfTree.left, ad);
        ad.add(pRootOfTree);
        inOrder(pRootOfTree.right, ad);
    }