Leetcode 112. Path Sum

Given a binary tree and a sum, determine if the tree has a root-to-leaf path such that adding up all the values along the path equals the given sum.

For example:
Given the below binary tree andsum = 22,

              5
             / \
            4   8
           /   / \
          11  13  4
         /  \      \
        7    2      1

return true, as there exist a root-to-leaf path5->4->11->2which sum is 22.

public class Solution {
    public void connect(TreeLinkNode root) {
        if(root == null || root.left == null) {  
            return;  
        }  
        root.left.next = root.right;    
        if(root.next != null) {  
            root.right.next = root.next.left;  
        }  
        connect(root.left);  
        connect(root.right);   
        return;  
    }
}