Merge Two Sorted Lists
You are given the heads of two sorted linked lists list1 and list2.
Merge the two lists into 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.
Example 1:
Input: list1 = [1,2,4], list2 = [1,3,4]
Output: [1,1,2,3,4,4]
Example 2:
Input: list1 = [], list2 = []
Output: []
Example 3:
Input: list1 = [], list2 = [0]
Output: [0]
Examples
Example 1
Input: list1 = [1,2,4], list2 = [1,3,4]
Output: [1,1,2,3,4,4]
Explanation: Compare nodes from both lists. 1<=1, take list1's 1. Then 1<=2 so take list2's 1. Then 2<=3 so take list1's 2. Then 3<=4, take list2's 3. Then 4=4, take list1's 4. Finally take list2's 4.
Example 2
Input: list1 = [], list2 = [0]
Output: [0]
Explanation: list1 is empty, so the result is simply list2.
Constraints
- -The number of nodes in both lists is in the range [0, 50].
- --100 <= Node.val <= 100
- -Both list1 and list2 are sorted in non-decreasing order.
Optimal Complexity
Time
O(n + m)
Space
O(1)
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