LeetCode 21. Merge Two Sorted Lists

You are given the heads of two sorted linked lists list1 and list2.

Merge the two lists in a one sorted list. The list should be made by splicing together the nodes of the first two lists.

Return the head of the merged linked list.

https://leetcode.com/problems/merge-two-sorted-lists/

Merge Two Sorted Lists - LeetCode

두 LinkedList의 대소관계를 따져 순차적으로 반환하는 문제이다. while을 쓰기전에 재귀로 풀 수 있는지를 따져보면 좀더 수월할 것 같다.

public ListNode mergeTwoLists(ListNode list1, ListNode list2) {
        if(list1 == null) return list2;
        if(list2 == null) return list1;
      
        
            if(list1.val > list2.val) {
                list2.next = mergeTwoLists(list2.next, list1);
                return list2;
            } else {
                list1.next = mergeTwoLists(list2, list1.next);
                return list1;
            }   
       
    }

참고 코드