[leetcode]Merge Two Sorted Lists

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public class Solution { public ListNode mergeTwoLists(ListNode l1, ListNode l2) { if (l1 == null) return l2; if (l2 == null) return l1; ListNode dummy = new ListNode(-1); ListNode current = dummy; while (l1 != null && l2 != null){ if (l1.val > l2.val){ current.next = l2; l2 = l2.next; }else{ current.next = l1; l1 = l1.next; } current = current.next; } while (l1 != null){ current.next = l1; l1 = l1.next; current = current.next; } while (l2 != null){ current.next = l2; l2 = l2.next; current = current.next; } return dummy.next; } }