Simple Java Solution O(n^2)
Intuition\n Describe your first thoughts on how to solve this problem. \n\n# Approach\n Describe your approach to solving the problem. \n\n# Complexity\n- Time 
# Intuition\n<!-- Describe your first thoughts on how to solve this problem. -->\n\n# Approach\n<!-- Describe your approach to solving the problem. -->\n\n# Complexity\n- Time complexity:\n<!-- Add your time complexity here, e.g. $$O(n)$$ -->\n\n- Space complexity:\n<!-- Add your space complexity here, e.g. $$O(n)$$ -->\n\n# Code\n```\n/**\n * Definition for singly-linked list.\n * public class ListNode {\n *     int val;\n *     ListNode next;\n *     ListNode() {}\n *     ListNode(int val) { this.val = val; }\n *     ListNode(int val, ListNode next) { this.val = val; this.next = next; }\n * }\n */\nclass Solution {\n    public ListNode mergeInBetween(ListNode list1, int a, int b, ListNode list2) {\n        ListNode head = list1;\n        for(int i = 1; i < a; i++) {\n            head = head.next;\n        }\n        ListNode temp = head;\n        for(int i = 0; i < b-a+2; i++) {\n            temp = temp.next;\n        }\n        ListNode temp2 = list2;\n        while(temp2.next != null) {\n            temp2 = temp2.next;\n        }\n        head.next = list2;\n        temp2.next = temp;\n        return list1;\n    }\n}\n```
['Linked List', 'Java']