Adyen Coding Interview Questions
25 Adyen coding interview problems with full optimal solutions — 11 easy, 11 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 Adyen interviewer values, and a FAQ section.
Showing 11 problems of 25
- #1easyfoundational
1. Two Sum
Given an array of integers and a target, return indices of two numbers that sum to the target.
- #2easyfoundational
2. Valid Parentheses
Given a string of brackets, determine if every opener has a matching, properly nested closer.
- #3easyfoundational
3. Merge Two Sorted Lists
Merge two sorted linked lists into a single sorted list in O(n+m).
- #4easyfoundational
4. Remove Duplicates from Sorted Array
Remove duplicates in-place from a sorted array and return the new length.
- #5easyfoundational
5. Best Time to Buy and Sell Stock
Given an array of daily prices, return the maximum profit from one buy and one sell.
- #6easyfoundational
6. Contains Duplicate
Return true if any value appears at least twice in the input array.
- #7easyfoundational
7. Valid Anagram
Given two strings, return true if one is an anagram of the other.
- #17easyfoundational
17. Reverse Linked List
Given the head of a singly linked list, reverse the list and return the new head.
- #18easyfoundational
18. Linked List Cycle
Detect whether a linked list contains a cycle.
- #19easyfoundational
19. Maximum Depth of Binary Tree
Return the maximum depth of a binary tree.
- #20easyfoundational
20. Invert Binary Tree
Invert a binary tree by swapping every node's left and right children.