MergeTwoSortedLists.java

/** 
 * Merge two sorted linked lists and return it as a new list. 
 * The new list should be made by splicing together the nodes of the first two lists. 
 */

public class MergeTwoSortedLists {
	public ListNode mergeTwoLists(ListNode l1, ListNode l2) {
		ListNode head = new ListNode(0);
		ListNode cur = head;
		while (l1 != null && l2 != null) {
			if (l1.val <= l2.val) {
				cur.next = l1;
				l1 = l1.next;
			} else {
				cur.next = l2;
				l2 = l2.next;
			}
			cur = cur.next;
		}
		if (l1 != null) {
			cur.next = l1;
		} else {
			cur.next = l2;
		}
		return head.next;
	}
}