Software Engineer Coding & Algorithms Interview Questions

Practice 2,712 real Coding & Algorithms interview questions for Software Engineer roles. From companies including Meta, Amazon, Google, Uber, Microsoft.

2.7k Questions 325 Companies08.11.2026
Showing 20 results
Role
Stripe logo
Stripe
Medium
Software Engineer

Convert bitmap into ASCII characters

Question Given an array/string of 0-1 bits representing a bitmap font, write code to render each character as a grid using '.' for 0 and '#' for 1, an...

Coding & Algorithms
13
0
51 people solved
Jul 29, 2025
Amazon logo
Amazon
Medium
Software Engineer

Find largest island area

Question Given a 2D grid of 0s and 1s, find the largest area of a connected group of 1s (island) using 4-directional adjacency; return that area. (Var...

Coding & Algorithms
14
0
21 people solved
Jul 29, 2025
DoorDash logo
DoorDash
Medium
Software Engineer

Count changed nodes in N-ary trees

Question Given two N-ary trees (old and new versions) where each node has a key (string), value (int), and list of children, compute how many nodes ar...

Coding & Algorithms
13
0
45 people solved
Jul 29, 2025
Meta logo
Meta
Medium
Software Engineer

Solve various LeetCode data-structure questions

Question LeetCode 129. Sum Root to Leaf Numbers LeetCode 2089. Find Target Indices After Sorting Array LeetCode 270. Closest Binary Search Tree Value ...

Coding & Algorithms
16
0
46 people solved
Jul 29, 2025
Meta logo
Meta
Medium
Software Engineer

Design prefix-sum function and max stack

Question LeetCode 303. Range Sum Query – Immutable (design a reusable prefix-sum function) LeetCode 716. Max Stack (similar design question) https://l...

Coding & Algorithms
4
0
15 people solved
Jul 29, 2025
Meta logo
Meta
Medium
Software Engineer

Find closest BST value and remove parentheses

Question LeetCode 270. Closest Binary Search Tree Value LeetCode 1249. Minimum Remove to Make Valid Parentheses (follow-up: achieve without using a st...

Coding & Algorithms
13
0
55 people solved
Jul 29, 2025
Meta logo
Meta
Medium
Software Engineer

Solve tree leaf sum and target indices search

Question LeetCode 129. Sum Root to Leaf Numbers LeetCode 2089. Find Target Indices After Sorting Array (array already sorted; require O(log n) time) h...

Coding & Algorithms
7
0
34 people solved
Jul 29, 2025
Talroo logo
Talroo
Medium
Software Engineer

Calculate area, flush probability, egg drops

Question Given two quarter-circles inside a 1×1 square (centers at bottom-left and top-right corners), find the exact area of their overlapping region...

Coding & Algorithms
85
0
284 people solved
Jul 29, 2025
Roblox logo
Roblox
Medium
Software Engineer

Detect shuffle-mode sequence

Question Given a playlist of distinct songs and two player modes—Random (each next song chosen independently and uniformly at random, with replacement...

Coding & Algorithms
103
0
167 people solved
Jul 29, 2025
DoorDash logo
DoorDash
Medium
Software Engineer

Find names similar by one swap

Question LeetCode 859. Buddy Strings – Given a target string and a list of strings, return all list entries that can match the target by swapping at m...

Coding & Algorithms
9
0
27 people solved
Jul 29, 2025
Meta logo
Meta
Medium
Software Engineer

Check Palindrome and Add Decimal Strings

Question LeetCode 266. Palindrome Permutation – Given a string, determine whether any permutation can form a palindrome. Follow-up: If a palindrome pe...

Coding & Algorithms
24
0
66 people solved
Jul 29, 2025
Character.AI logo
Character.AI
Medium
Software Engineer

Design timestamped key-value map

Question Design a class that supports insert(key, value, timestamp) and get(key, timestamp) where get returns the value whose timestamp is the smalles...

Coding & Algorithms
16
0
42 people solved
Jul 29, 2025
Meta logo
Meta
Medium
Software Engineer

Handle palindrome & decimal addition

Question LeetCode 266. Palindrome Permutation Given two non-negative decimal number strings, implement addition that supports a decimal point. https:/...

Coding & Algorithms
11
0
35 people solved
Jul 29, 2025
Character.AI logo
Character.AI
Medium
Software Engineer

Explain strings and copy complexity

Question What is a string? What fields does a struct string contain, and how would you implement it yourself? What is the time complexity of copying a...

Coding & Algorithms
4
0
15 people solved
Jul 29, 2025
xAI logo
xAI
Medium
Software Engineer

Explain strings, moves, and concurrency

Question What is a string in programming languages? What fields are stored in a typical struct string and how would you implement one yourself? What i...

Coding & Algorithms
24
0
68 people solved
Jul 29, 2025
Meta logo
Meta
Medium
Software Engineer

Solve vertical order & diameter variants

Question LeetCode 314. Binary Tree Vertical Order Traversal LeetCode 543. Diameter of Binary Tree – modified to return the number of nodes (edges + 1)...

Coding & Algorithms
1
0
4 people solved
Jul 29, 2025
Amazon logo
Amazon
Medium
Software Engineer

Solve array and list algorithms

Question LeetCode 315. Count of Smaller Numbers After Self LeetCode 23. Merge k Sorted Lists Design algorithm for Amazon Locker getPackage (retrieve p...

Coding & Algorithms
5
0
14 people solved
Jul 29, 2025
Amazon logo
Amazon
Medium
Software Engineer

Compute minimum passes to collect numbers

Question You are given an array shelf of n distinct integers that is a permutation of 1…n. Starting with target = 1, you repeatedly scan shelf from le...

Coding & Algorithms
76
0
200 people solved
Jul 29, 2025
Amazon logo
Amazon
Medium
Software Engineer

Compute maximum distinct-product pickup days

Question Given an array of positive integers representing quantities of different products, on day i (starting from 1) you must pick exactly i distinc...

Coding & Algorithms
21
0
56 people solved
Jul 29, 2025
Snapchat logo
Snapchat
Medium
Software Engineer

Determine blockage and parse HTML tokens

Question Given a set of 2-D circular stones, determine whether they can completely block the width of a river. You may define the input format. Given ...

Coding & Algorithms
19
0
52 people solved
Jul 29, 2025

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