Chime Coding Interview Questions
25 Chime coding interview problems with full optimal solutions — 14 easy, 8 medium, 3 hard. Every problem ships with multiple approaches (brute-force first, then the optimal), complexity tables for each, company-specific tips on what an Chime interviewer values, and a FAQ section.
- #1easyfoundational
1. Two Sum
Given an array of integers and a target, return indices of the two numbers that sum to the target.
- #2easyfoundational
2. Valid Parentheses
Given a string containing brackets, determine if every opening bracket is properly closed in the right order.
- #3easyfoundational
3. Merge Two Sorted Lists
Merge two sorted linked lists into one sorted list by splicing nodes together.
- #4easyfoundational
4. Remove Duplicates from Sorted Array
Remove duplicates in-place from a sorted array, returning the new length.
- #5easyfoundational
5. Remove Element
Remove all occurrences of a value in-place from an array and return the new length.
- #6easyfoundational
6. Search Insert Position
Given a sorted array and a target, return the index where the target is or should be inserted.
- #7easyfoundational
7. Plus One
Given a non-empty array representing digits of an integer, increment by one and return the array.
- #8easyfoundational
8. Merge Sorted Array
Merge two sorted arrays in-place into the first array, which has enough trailing space.
- #9easyfoundational
9. Binary Tree Inorder Traversal
Return the inorder traversal of a binary tree's node values.
- #10easyfoundational
10. Single Number
Given a non-empty array where every element appears twice except one, find that single element in O(n) time and O(1) space.
- #11easyfoundational
11. Linked List Cycle
Detect whether a singly linked list has a cycle using O(1) extra space.
- #12easyfoundational
12. Best Time to Buy and Sell Stock
Given an array of daily prices, find the maximum profit from a single buy-then-sell pair.
- #13easyfoundational
13. Symmetric Tree
Determine whether a binary tree is a mirror of itself around its center.
- #14easyfoundational
14. Maximum Depth of Binary Tree
Return the maximum depth of a binary tree, defined as the number of nodes along the longest root-to-leaf path.
- #15mediumfoundational
15. LRU Cache
Design a Least Recently Used cache with O(1) get and put operations.
- #16mediumfoundational
16. Word Break
Determine if a string can be segmented into a space-separated sequence of dictionary words.
- #17mediumfoundational
17. Number of Islands
Count the number of connected land regions in a 2D grid of land and water cells.
- #18mediumfoundational
18. Course Schedule
Given prerequisite pairs over n courses, determine whether you can finish all courses (i.e., the dependency graph is acyclic).
- #19mediumfoundational
19. Kth Largest Element in an Array
Find the kth largest element in an unsorted array without fully sorting it.
- #20mediumfoundational
20. Coin Change
Compute the fewest number of coins from given denominations that sum to a target amount, or -1 if impossible.
- #21mediumfoundational
21. Top K Frequent Elements
Return the k most frequent elements in an integer array in better-than-O(n log n) time.
- #22mediumfoundational
22. House Robber
Given non-negative house values, compute the maximum amount you can rob without picking two adjacent houses.
- #23hardfoundational
23. Sliding Window Maximum
Return the maximum of every contiguous window of size k as it slides across the array.
- #24hardfoundational
24. Serialize and Deserialize Binary Tree
Design serialize() and deserialize() functions that round-trip an arbitrary binary tree through a string.
- #25hardfoundational
25. Burst Balloons
Maximize the coins you collect by bursting balloons in an optimal order, where the gain from a burst depends on its current neighbors.