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,
1
/ 2 3
/ \ 4 5 7
After calling your function, the tree should look like:
1 -> NULL
/ 2 -> 3 -> NULL
/ \ 4-> 5 -> 7 -> NULL
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/** * Definition for binary tree with next pointer.
* struct TreeLinkNode {
* int val;
* TreeLinkNode *left, *right, *next;
* TreeLinkNode(int x) : val(x), left(NULL), right(NULL), next(NULL) {}
* };
*/
class
Solution {
public:
void
connect(TreeLinkNode *root) {
while
(root) {
TreeLinkNode * next = NULL; // the first node of next level
TreeLinkNode * prev = NULL; // previous node on the same level
for
(; root; root=root->next) {
if
(!next) next = root->left?root->left:root->right;
if
(root->left) {
if
(prev) prev->next = root->left;
prev = root->left;
}
if
(root->right) {
if
(prev) prev->next = root->right;
prev = root->right;
}
}
root = next; // turn to next level
}
}
}; |