Leetcode 116. fill in the next right node pointer of each node

Title Description

116. Fill in the next right node pointer for each node

solution :

First solve it recursively , Our approach is to connect every two adjacent nodes , That's it $node1.left\to node1.right$ ,$node2.left\to node2.right$,$node1.right\to node2.left$

/* // Definition for a Node. class Node { public: int val; Node* left; Node* right; Node* next; Node() : val(0), left(NULL), right(NULL), next(NULL) {} Node(int _val) : val(_val), left(NULL), right(NULL), next(NULL) {} Node(int _val, Node* _left, Node* _right, Node* _next) : val(_val), left(_left), right(_right), next(_next) {} }; */

class Solution {
    
public:
    Node* connect(Node* root) {
    
        if (root == nullptr) return root;
        connectTwoNode(root->left, root->right);
        return root;
    }

    void connectTwoNode(Node* node1, Node* node2){
    
        if (node1 == nullptr || node2 == nullptr) return;

        node1->next = node2;

        connectTwoNode(node1->left, node1->right);
        connectTwoNode(node2->left, node2->right);
        connectTwoNode(node1->right, node2->left);


    }
};