标签:
Given a binary tree
struct TreeLinkNode { TreeLinkNode *left; TreeLinkNode *right; TreeLinkNode *next; }
Populate each next pointer to point to its next right node. If there is no next right node, the next pointer should be set to NULL
.
Initially, all next pointers are set to NULL
.
Note:
For example,
Given the following perfect binary tree,
1 / 2 3 / \ / 4 5 6 7
After calling your function, the tree should look like:
1 -> NULL / 2 -> 3 -> NULL / \ / 4->5->6->7 -> NULL
问题: 给定一个二叉树,将树元素的 *next 指向该元素在树结构中的水平右边节点。
这是广度遍历的一个应用。可以借组队列结构实现广度遍历,求解题目。
思路:
将根节点塞进队列,即实现了上面思路的初始化。
1 void connect(TreeLinkNode *root) { 2 3 if(root == NULL){ 4 return; 5 } 6 7 list<TreeLinkNode*> queue; 8 9 queue.push_back(root); 10 11 while(queue.size() > 0 ){ 12 13 // assign value to the next point of the node in queue. 14 list<TreeLinkNode*>::iterator q_iter; 15 for( q_iter = queue.begin() ; std::next(q_iter,1) != queue.end(); q_iter++){ 16 (*q_iter)->next = *std::next(q_iter,1); 17 } 18 19 // pop each node in the current row in the tree structure, and push the left and right childrens of them into queue. 20 while(queue.front()->next != NULL){ 21 TreeLinkNode* node = queue.front(); 22 queue.pop_front(); 23 24 if(node->left != NULL){ 25 queue.push_back(node->left); 26 } 27 28 if(node->right != NULL){ 29 queue.push_back(node->right); 30 } 31 } 32 33 TreeLinkNode* node = queue.front(); 34 queue.pop_front(); 35 36 if(node->left != NULL){ 37 queue.push_back(node->left); 38 } 39 40 if(node->right != NULL){ 41 queue.push_back(node->right); 42 } 43 } 44 }
[LeetCode] 116. Populating Next Right Pointers in Each Node 解决思路
标签:
原文地址:http://www.cnblogs.com/TonyYPZhang/p/5118051.html