Postman Coding Interview Questions
32 Postman coding interview problems with full optimal solutions — 10 easy, 17 medium, 5 hard. Every problem ships with multiple approaches (brute-force first, then the optimal), complexity tables for each, company-specific tips on what an Postman interviewer values, and a FAQ section.
Showing 17 problems of 32
- #10mediumfoundational
10. Add Two Numbers
Add two numbers represented by linked lists in reverse-digit order.
- #11mediumfoundational
11. Longest Substring Without Repeating Characters
Find the length of the longest substring without repeating characters.
- #12mediumfoundational
12. Group Anagrams
Group strings into lists where each list contains anagrams of each other.
- #13mediumfoundational
13. LRU Cache
Design a least-recently-used cache with O(1) get and put.
- #14mediumfoundational
14. 3Sum
Find all unique triplets in the array that sum to zero.
- #15mediumfoundational
15. Container With Most Water
Find two vertical lines that with the x-axis form a container holding the most water.
- #16mediumfoundational
16. Spiral Matrix
Return all elements of an m x n matrix in spiral order.
- #17mediumfoundational
17. Word Break
Decide whether a string can be segmented into a sequence of dictionary words.
- #18mediumfoundational
18. Number of Islands
Count connected components of land cells in a 2D grid.
- #19mediumfoundational
19. Coin Change
Return the fewest number of coins needed to make up an amount, or -1 if impossible.
- #20mediumfoundational
20. Clone Graph
Deep-copy a connected undirected graph given a node reference.
- #21mediumfoundational
21. Course Schedule
Decide whether all courses can be completed given prerequisite pairs (cycle detection).
- #26mediumfoundational
26. Maximum Subarray
Find the contiguous subarray with the largest sum.
- #27mediumfoundational
27. Product of Array Except Self
Return an array where each element is the product of all other elements, without using division.
- #29mediumfoundational
29. Word Search
Check whether a word can be formed in a 2D grid by traversing adjacent cells.
- #30mediumfoundational
30. Implement Trie (Prefix Tree)
Implement a trie supporting insert, search, and prefix-search in O(L).
- #32mediumfoundational
32. Longest Palindromic Substring
Find the longest palindromic substring within a given string.