How often are these problems asked?
Frequency scores are based on crowdsourced interview reports. A higher score means the problem has been reported more often in recent HCL interviews.
Very Likely
75-100%
Likely
50-74%
Sometimes
25-49%
Rare
0-24%
Problem database last updated: June 20, 2025
H
HCL Coding Interview Questions
9 problems · 6 Easy, 3 Medium, 0 Hard · Ranked #151 of 458
Difficulty breakdown
6 Easy
67% · avg 23%
3 Medium
33% · avg 59%
0 Hard
0% · avg 18%
Top topics
string
55.6%2x
array
55.6%
two-pointers
33.3%2.5x
sorting
33.3%2.3x
hash-table
22.2%
stack
11.1%
Interview profile
Based on 9 reported problems, HCL interviews are easier than average - only 0% Hard compared to 18% across all companies.
Compared to the industry average, HCL puts unusual emphasis on two-pointers (33.3% of problems, 2.5x the industry average), sorting (33.3% of problems, 2.3x the industry average), string (55.6% of problems, 2x the industry average). If you're short on time, these are the categories to double down on.
The most common topics are string (55.6%), array (55.6%), two-pointers (33.3%), sorting (33.3%). Problems below are sorted by frequency, the ones at the top are asked most often.
All 9 problems
| Problem | Difficulty | Frequency | Topics | |
|---|---|---|---|---|
Valid Parentheses Given a string s containing just the characters '(', ')', '{', '}', '[' and ']', determine if the input string is valid. | Easy | Very Likely | stringstack | Solve |
Longest Substring Without Repeating Characters Given a string s, find the length of the longest substring without duplicate characters. | Medium | Very Likely | hash-tablestringsliding-window | Solve |
Merge Sorted Array You are given two integer arrays nums1 and nums2, sorted in non-decreasing order, and two integers m and n, representing the number of elements in nums1 and num... | Easy | Very Likely | arraytwo-pointerssorting | Solve |
Palindrome Number Given an integer x, return true if x is a palindrome, and false otherwise. | Easy | Very Likely | math | Solve |
3Sum Given an integer array nums, return all the triplets [nums[i], nums[j], nums[k]] such that i != j, i != k, and j != k, and nums[i] + nums[j] + nums[k] == 0. | Medium | Very Likely | arraytwo-pointerssorting | Solve |
Longest Common Prefix Write a function to find the longest common prefix string amongst an array of strings. | Easy | Very Likely | arraystringtrie | Solve |
Two Sum Given an array of integers nums and an integer target, return the indices of the two numbers that add up to target. | Easy | Very Likely | arrayhash-map | Solve |
Group Anagrams Given an array of strings strs, group the anagrams together. You can return the answer in any order. | Medium | Very Likely | arrayhash-tablestring | Solve |
Reverse String Write a function that reverses a string. The input string is given as an array of characters s. | Easy | Very Likely | two-pointersstring | Solve |
Valid Parentheses
SolveGiven a string s containing just the characters '(', ')', '{', '}', '[' and ']', determine if the input string is valid.
EasyVery Likely
stringstack
Longest Substring Without Repeating Characters
SolveGiven a string s, find the length of the longest substring without duplicate characters.
MediumVery Likely
hash-tablestringsliding-window
Merge Sorted Array
SolveYou are given two integer arrays nums1 and nums2, sorted in non-decreasing order, and two integers m and n, representing the number of elements in nums1 and num...
EasyVery Likely
arraytwo-pointerssorting
Palindrome Number
SolveGiven an integer x, return true if x is a palindrome, and false otherwise.
EasyVery Likely
math
3Sum
SolveGiven an integer array nums, return all the triplets [nums[i], nums[j], nums[k]] such that i != j, i != k, and j != k, and nums[i] + nums[j] + nums[k] == 0.
MediumVery Likely
arraytwo-pointerssorting
Longest Common Prefix
SolveWrite a function to find the longest common prefix string amongst an array of strings.
EasyVery Likely
arraystringtrie
Two Sum
SolveGiven an array of integers nums and an integer target, return the indices of the two numbers that add up to target.
EasyVery Likely
arrayhash-map
Group Anagrams
SolveGiven an array of strings strs, group the anagrams together. You can return the answer in any order.
MediumVery Likely
arrayhash-tablestring
Reverse String
SolveWrite a function that reverses a string. The input string is given as an array of characters s.
EasyVery Likely
two-pointersstring
Preparing for your HCL coding interview
HCL interviews focus heavily on string, array, two-pointers problems. If you're short on time, these are the categories to prioritize. The problems on this page are sorted by frequency, so start from the top and work your way down.
Beyond solving problems, practice explaining your approach. HCL interviewers care about your thought process - how you break down a problem, consider edge cases, and evaluate tradeoffs between solutions. A clean O(n) solution you can explain clearly beats an O(log n) solution you can't articulate.
Looking for more companies? Browse all 458 companies in our directory, or sharpen your fundamentals with our free data structure visualizers and AI-powered DSA tutor.
Frequently Asked Questions
What coding problems does HCL ask in interviews?add
HCL has been reported to ask 9 distinct coding problems. The most common topics are string, array, two-pointers. 6 are Easy difficulty, 3 are Medium, and 0 are Hard. Problems are sorted by frequency - the ones at the top are asked most often.
How hard are HCL coding interviews?add
Based on 9 reported problems, HCL interviews are easier than average - only 0% Hard compared to 18% across all companies. 33% of questions are Medium difficulty. Focus on the high-frequency Medium problems first, then work through the Hard ones.
How should I prepare for a HCL coding interview?add
Start with the highest-frequency problems listed on this page. Focus on the core topics: string, array, two-pointers. Practice solving them under time pressure and explaining your approach out loud. Mock interviews with AI can simulate the real experience.
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