# Populating Next Right Pointers in Each Node II LeetCode Solution Share:

Populating Next Right Pointers in Each Node II Given a binary tree

```struct Node {
int val;
Node *left;
Node *right;
Node *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`.

Example 1:

```Input: root = [1,2,3,4,5,null,7]
Output: [1,#,2,3,#,4,5,7,#]
Explanation: Given the above binary tree (Figure A), your function should populate each next pointer to point to its next right node, just like in Figure B. The serialized output is in level order as connected by the next pointers, with '#' signifying the end of each level.
```

Example 2:

```Input: root = []
Output: []
```

Constraints:

• The number of nodes in the tree is in the range `[0, 6000]`.
• `-100 <= Node.val <= 100`

Time: O(n)
Space: O(1)

### C++

``````class Solution {
public:
Node* connect(Node* root) {
Node* node = root;  // the node just above current needling

while (node) {
Node dummy(0);  // dummy node before needling
// needle children of node
for (Node* needle = &dummy; node; node = node->next) {
if (node->left) {  // needle left child
needle->next = node->left;
needle = needle->next;
}
if (node->right) {  // needle right child
needle->next = node->right;
needle = needle->next;
}
}
node = dummy.next;  // move node to the next level
}

return root;
}
};
``````

### Java

`````` class Solution {
public Node connect(Node root) {
Node node = root; // the node just above current needling

while (node != null) {
Node dummy = new Node(); // dummy node before needling
// needle children of node
for (Node needle = dummy; node != null; node = node.next) {
if (node.left != null) { // needle left child
needle.next = node.left;
needle = needle.next;
}
if (node.right != null) { // needle right child
needle.next = node.right;
needle = needle.next;
}
}
node = dummy.next; // move node to the next level
}

return root;
}
}

``````

### Python

``````class Solution:
def connect(self, root: 'Node') -> 'Node':
node = root  # the node just above current needling

while node:
dummy = Node(0)  # dummy node before needling
# needle children of node
needle = dummy
while node:
if node.left:  # needle left child
needle.next = node.left
needle = needle.next
if node.right:  # needle right child
needle.next = node.right
needle = needle.next
node = node.next
node = dummy.next  # move node to the next level

return root

``````

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