Software Engineer · Full Journey · Coding

Apple — Software Engineer ✅ Passed

Level: Unknown Level

Round: Full Journey · Type: Coding · Difficulty: 5/10 · Duration: 60 min · Interviewer: Neutral

Topics: Data Structures, Arrays, Algorithms, Strings, HashMaps, Graphs, BFS, DFS, Linked Lists, Matrix Manipulation, Sorting, Heaps, Sliding Window, Topological Sort, Cycle Detection, Priority Queue

Location: San Francisco Bay Area

Interview date: 2026-01-15

Summary

I reviewed a collection of Apple Software Engineer interview questions from Reddit and LeetCode Discuss. Apple coding interviews typically focus on LeetCode Easy to Medium level problems, with a strong emphasis on code...

Details

I reviewed common questions for Apple Software Engineer interviews:

Data Structure Design

1. LRU Cache:
   • Implement get(key) and put(key, value) in O(1) time complexity.
   • Classic solution: HashMap + Doubly Linked List.
2. Insert Delete GetRandom O(1):
   • Implement a data structure with insert(val), remove(val), and getRandom() with an average O(1) time complexity.
   • Solution: HashMap + Array.
3. Implement Trie (Prefix Tree):
   • Implement insert(word), search(word), and startsWith(prefix).

Arrays / High-Frequency Algorithms

1. Top K Frequent Elements:
   • Given nums = [1,1,1,2,2,3] and k = 2, return [1,2].
   • Solution: HashMap + Heap.
2. Product of Array Except Self:
   • Given [1,2,3,4], return [24,12,8,6] without using division in O(n) time.
3. Trapping Rain Water:
   • Given height = [0,1,0,2,1,0,1,3,2,1,2,1], calculate how much water can be stored.
4. Container With Most Water:
   • A two-pointer problem calculating the maximum water between two pillars.

Strings / HashMap

1. Longest Substring Without Repeating Characters:
   • Classic sliding window problem.
   • abcabcbb → 3
2. Group Anagrams:
   • Input: ["eat","tea","tan","ate","nat","bat"]
   • Output: [["eat","tea","ate"],["tan","nat"],["bat"]]
3. Decode String:
   • Input: 3[a2[c]]
   • Output: accaccacc
   • Implemented using a stack.

Graphs / BFS / DFS

1. Number of Islands:
   • Classic BFS / DFS to count the number of islands.
2. Course Schedule:
   • Determine if courses can be completed using topological sort and cycle detection.

Linked Lists

1. Merge K Sorted Lists:
   • Example:
     • 1->4->5
     • 1->3->4
     • 2->6
   • Output: 1->1->2->3->4->4->5->6 using a Priority Queue.

Matrix

1. Rotate Image (Rotate Matrix 90°):
   • Input:
     • 1 2 3
     • 4 5 6
     • 7 8 9
   • Output:
     • 7 4 1
     • 8 5 2
     • 9 6 3
   • Solution: transpose, then reverse rows.

Advanced Array

1. Maximum Length of Mountain in Array:
   • Example: [2,1,4,7,3,2,5]
   • Longest mountain: 1,4,7,3,2 with length = 5.

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