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/**

Definition for singlylinked list.

public class ListNode {

int val;

ListNode next;

ListNode(int x) { val = x; }

}
*/
public class Solution {
public ListNode mergeTwoLists(ListNode l1, ListNode l2)
{
if(l1 == null)
return l2;
if(l2 == null)
return l1;ListNode headToReturn; if(l1.val < l2.val) { headToReturn = l1; l1 = l1.next; } else { headToReturn = l2; l2 = l2.next; } ListNode runner = headToReturn; while(l1 != null && l2 != null) { if(l1.val < l2.val) { runner.next = l1; l1 = l1.next; } else { runner.next = l2; l2 = l2.next; } runner = runner.next; } if(l1 != null) runner.next = l1; if(l2 != null) runner.next = l2; return headToReturn;
}
}
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