merge_sorted_lists.py

###  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.

# 1 step: create a new list with descending indices
# 2 step : 


class ListNode:
    def __init__(self, val=0, next=None):
        self.val = val
        self.next = next

class Solution(object):
    def mergeTwoLists(self, list1, list2):
        """
        :type list1: Optional[ListNode]
        :type list2: Optional[ListNode]
        
        :rtype: Optional[ListNode]
        """
        node = ListNode()
        curr = node

        while list1 and list2:
            if list1.val < list2.val:
                curr.next = list1
                list1 = list1.next
            else:
                curr.next = list2
                list2 = list2.next
            curr = curr.next 


        curr.next = list1 if list1 else list2

        return node.next