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Populating Next Right Pointers in Each Node
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:
- You may only use constant extra space.
- You may assume that it is a perfect binary tree (ie, all leaves are at the same level, and every parent has two children).
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
1 /** 2 * Definition for binary tree with next pointer. 3 * struct TreeLinkNode { 4 * int val; 5 * TreeLinkNode *left, *right, *next; 6 * TreeLinkNode(int x) : val(x), left(NULL), right(NULL), next(NULL) {} 7 * }; 8 */ 9 class Solution {10 public:11 void connect(TreeLinkNode *root) {12 if (!root || !root->left) return;13 14 root->left->next = root->right;15 if (root->next)16 root->right->next = root->next->left;17 18 connect(root->left);19 connect(root->right);20 }21 };
1 /** 2 * Definition for binary tree with next pointer. 3 * struct TreeLinkNode { 4 * int val; 5 * TreeLinkNode *left, *right, *next; 6 * TreeLinkNode(int x) : val(x), left(NULL), right(NULL), next(NULL) {} 7 * }; 8 */ 9 class Solution {10 public:11 void connect(TreeLinkNode *root) {12 if (!root || !root->left) return;13 14 queue<TreeLinkNode* > qu;15 qu.push(root);16 while (!qu.empty()) {17 int n = qu.size();18 while (n--) {19 TreeLinkNode* temp = qu.front();20 qu.pop();21 22 if (temp->left) {23 qu.push(temp->left);24 qu.push(temp->right);25 temp->left->next = temp->right;26 if (temp->next)27 temp->right->next = temp->next->left;28 } else {29 return;30 }31 }32 }33 }34 };
Populating Next Right Pointers in Each Node
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