LeetCode114 Flatten Binary Tree to Linked List 二叉树扁平化

Given a binary tree, flatten it to a linked list in-place.

For example, given the following tree:

    1
   / \
  2   5
 / \   \
3   4   6

The flattened tree should look like:

1
 \
  2
   \
    3
     \
      4
       \
        5
         \
          6

题源：here；完整实现：here

思路：

通过递归遍历二叉树，发现二叉树有左子树时将左子树插入根节点和右子树之间。

void flatten(TreeNode* root) {
	if (!root) return;
	if (root->left){
		flatten(root->left);
		TreeNode* oldRight = root->right, *currRight = root->left;
		root->right = root->left;
		while (currRight->right) currRight = currRight->right;
		currRight->right = oldRight;
		root->left = NULL;
	}			
	flatten(root->right);
}

 纪念贴图：

在这里说明一下，如果你想要运行时间在某个阶段的代码，可以单击柱状图来查看，如下图：