Merge Two Sorted Lists Easy 0 attempts
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Merge Two Sorted Lists

Easy Linked List LeetCode

Merge two sorted linked lists into one sorted list.

Example: l1 = [1,2,4], l2 = [1,3,4] → Output: [1,1,2,3,4,4]

Sample Input
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Sample Output
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Constraints
  • 0 to 50 nodes per list
  • -100 <= Node.val <= 100
Test Cases
Case 1
Args: [[1,2,4],[1,3,4]] Expected: [1,1,2,3,4,4]
Topics
Linked List

Iterative Merge

function mergeTwoLists(l1, l2) {
  const dummy = {val: 0, next: null};
  let curr = dummy;
  while (l1 && l2) {
    if (l1.val <= l2.val) { curr.next = l1; l1 = l1.next; }
    else { curr.next = l2; l2 = l2.next; }
    curr = curr.next;
  }
  curr.next = l1 || l2;
  return dummy.next;
}

Time: O(m + n) | Space: O(1)

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