#0273

Merge Two Sorted Linked Lists

EasyDSA18 min10 XP

Problem

Two linked lists are provided as sorted value arrays. Return the sorted values after merging them the same way you would merge two sorted linked lists node by node.

Why This Matters

Merging sorted lists is the core operation behind merge sort and many linked-list interview questions.

Function Signature

def merge_two_lists(a, b):

Examples

Example 1

Inputa = [1,2,4], b = [1,3,4]

Output[1, 1, 2, 3, 4, 4]

Always take the smaller current value, then append the remaining tail.

Constraints

Return the exact requested value.
Handle edge cases cleanly.
Use the intended DSA pattern when brute force would scale poorly.

CodePython

def merge_two_lists(a, b):
    """
    Input example: a = [1,2,4], b = [1,3,4]
    Return: [1, 1, 2, 3, 4, 4]
    Return the value from the function so the tests can compare it. Do not print unless the prompt asks.
    """
    # write your code here
    return []

def merge_two_lists(a, b):
    """
    Input example: a = [1,2,4], b = [1,3,4]
    Return: [1, 1, 2, 3, 4, 4]
    Return the value from the function so the tests can compare it. Do not print unless the prompt asks.
    """
    # write your code here
    return []

Visible browser tests run here when available.

Testcases2 visible / 3 hidden categories

Two non-empty lists

Input[1,2,4], [1,3,4]

Expected[1, 1, 2, 3, 4, 4]

The values interleave in sorted order.

One empty list

Input[], [0]

Expected[0]

The remaining list becomes the answer.

Hidden Test Categories

duplicate valuesnegative valuesone list much longer