Intersection of Two Linked Lists

Problem

Two chains share a common tail. Return the first shared node value, or null. The shared tail is supplied explicitly.

Examples

Example 1

Input: {"a":[4,1],"b":[5,6,1],"shared":[8,4,5]}

Output: 8

Example 2

Input: {"a":[1],"b":[2],"shared":[]}

Output: null

Input and output use JSON-compatible values. For linked-list and tree questions, arrays represent the node structure as described above. Your code should implement solve(input).

Write your solutionImplement solve(input). Your draft is saved in this browser.

Compiler

How to solve Intersection of Two Linked Lists

Two chains share a common tail. Return the first shared node value, or null. The shared tail is supplied explicitly. Shared nodes are identical objects, not simply equal values. The reference implementation illustrates this approach; check the example and edge cases.

Time and space complexity

O(n+m) traversal time and O(1) space for the pointer-switching approach.

Practise and improve

Choose JavaScript, TypeScript or Python, complete the starter code, then select Run Tests. Request a hint when you need guidance, or choose View solution and confirm if you would like to study the reference implementation.