leetcode 117 Populating Next Right Pointers in Each Node II

最新推荐文章于 2021-01-29 16:34:55 发布

walter1990

最新推荐文章于 2021-01-29 16:34:55 发布

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本文介绍了一种在任意二叉树中填充每个节点的下一个右侧指针的方法，并提供了一个使用常数额外空间的解决方案。

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Follow up for problem "Populating Next Right Pointers in Each Node".

What if the given tree could be any binary tree? Would your previous solution still work?

Note:

You may only use constant extra space.

For example,
Given the following binary tree,

After calling your function, the tree should look like:

         1 -> NULL
       /  \
      2 -> 3 -> NULL
     / \    \
    4-> 5 -> 7 -> NULL

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class Solution {
public:
	void connect(TreeLinkNode *root) {
		if(root == NULL) return;
		while(true) {
			TreeLinkNode *node=NULL, *temp=NULL;
			bool flag=false;

			for(; root!=NULL; root=root->next) {
				node = root->left;
				flag = false;
				if(node==NULL) {
					node = root->right;
					flag = true;
				}
				if(node!=NULL) break;
			}

			temp = node;
			int cnt=1;
			if(node==NULL) break;
			if(flag) {
				cnt++;
				root = root->next;
			}
			for(; root!=NULL; root=root->next) {

				if(cnt>1) {
					if(root->left!=NULL) {
						node->next = root->left;
						node = root->left;
					}
				}

				node->next = root->right;
				if(node->next!=NULL)
					node = node->next;
				cnt++;
			}

			root = temp;
		}

		return;
	}
}