TCS coding questions (2026)

By Aayush Kumar Gupta · Last updated 3 Nov 2026 · 248 questions tracked

Short answer: In this list, TCS Ninja questions are all Easy, Digital is mostly Medium and Prime is mostly Hard. Start with the main TCS top 10, then move to the list for the role you are aiming at.

TCS hires freshers through the TCS NQT. Based on how you do, you are considered for Ninja, Digital or Prime, and the coding questions get harder at each step. So it makes sense to prepare for the role you actually want, not just "TCS" in general.

The 10 to practise first

Sorted by how recently and how often TCS asked them. The line under each one is the trick that cracks it.

1.
Best Time to Buy and Sell Stock · EasyAsked recently
Walk once, remember the lowest price so far, and check today's price minus that. One pass, no extra array.
Array, DP
2.
Container With Most Water · MediumAsked recently
Two pointers at both ends. Always move the shorter wall, because the taller one can't help you anymore.
Array, Two Pointers, Greedy
3.
Two Sum · EasyAsked recently
One pass with a hash map: for each number, check whether target minus it is already in the map.
Array, Hash Table
4.
Longest Palindromic Substring · MediumAsked recently
Expand around every centre, both odd and even length. O(n^2) and much easier to get right than the DP table.
Two Pointers, String, DP
5.
Roman to Integer · EasyAsked recently
Go left to right. If a symbol is smaller than the one after it, subtract it; otherwise add it.
Hash Table, Math, String
6.
First Missing Positive · HardAsked recently
Put every number x at index x-1 by swapping. Then the first index that doesn't hold the right number is your answer. O(n), no extra space.
Array, Hash Table
7.
Merge Sorted Array · EasyAsked recently
Fill from the back. Start from the ends of both arrays so you never overwrite something you still need.
Array, Two Pointers, Sorting
8.
Remove Duplicates from Sorted Array · EasyAsked recently
One slow pointer marks where the next unique value goes; the fast pointer scans. Return the slow pointer's count.
Array, Two Pointers
9.
Valid Anagram · EasyAsked recently
Count letters in one string, subtract for the other, and check that everything is back to zero.
Hash Table, String, Sorting
10.
Fibonacci Number · EasyAsked recently
Don't write the plain recursive version in an interview. Loop with two variables, or memoise if they ask for recursion.
Math, DP, Recursion

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What TCS asks most

By topic: Array (58%), Hash Table (21%), String (21%), Math (17%) and Two Pointers (16%). By level, 43% of the list is Easy, 47% Medium and 10% Hard. 38 of the 248 were asked in the last 3 months.

TCS questions by topic

Array (144 of 248)

1.
Find Missing Elements · EasyAsked recently
Array, Hash Table, Sorting
2.
Peak Index in a Mountain Array · MediumAsked recently
Binary search: if arr[mid] < arr[mid+1] you're still climbing, so go right.
Array, Binary Search, Ternary Search
3.
Two Sum II - Input Array Is Sorted · MediumAsked recently
The array is sorted, so use two pointers from both ends: sum too small, move left; too big, move right.
Array, Two Pointers, Binary Search

Hash Table (52 of 248)

1.
Group Anagrams · MediumAsked recently
Use the sorted word (or a 26-letter count) as the key of a hash map, and collect words under it.
Array, Hash Table, String
2.
Integer to Roman · MediumAsked recently
Greedy with a table that already includes 900, 400, 90, 40, 9 and 4. Keep taking the biggest value that fits.
Hash Table, Math, String
3.
Longest Consecutive Sequence · MediumAsked recently
Put everything in a set. Only start counting from x when x-1 isn't in the set, so each run is counted once. O(n).
Array, Hash Table, Union Find

String (51 of 248)

1.
Valid Palindrome · EasyAsked recently
Two pointers from both ends, skip anything that isn't a letter or digit, compare in lowercase.
Two Pointers, String
2.
Valid Parentheses · EasyAsked recently
Stack. Push opening brackets; on a closing one, the top must be its match. The stack must be empty at the end.
String, Stack, Bracket Sequences
3.
Longest Common Prefix · EasyAsked recently
Compare letter by letter across all words and stop at the first mismatch. Or sort and compare only the first and last word.
Array, String, Trie

Math (43 of 248)

1.
Integer Break · MediumAsked recently
Break the number into as many 3s as you can (use a 4 instead of 3+1). DP also works if you want to show the reasoning.
Math, DP
2.
Palindrome Number · EasyAsked recently
Negative numbers are out. Reverse only half the digits and compare, so there's no overflow to worry about.
Math
3.
Evaluate Reverse Polish Notation · MediumAsked recently
Stack of numbers. On an operator, pop two, apply it (second popped is the left side), push the result. Division truncates towards zero.
Array, Math, Stack

Two Pointers (39 of 248)

1.
3Sum · MediumAsked recently
Sort first. Fix one number, then run two pointers on the rest. Skip duplicates or you'll print the same triplet twice.
Array, Two Pointers, Sorting
2.
Palindrome Linked List · EasyAsked recently
Find the middle with slow and fast pointers, reverse the second half, then compare both halves.
Linked List, Two Pointers, Stack
3.
Reorder List · MediumAsked recently
Three steps: find the middle, reverse the second half, then merge the two halves one node at a time.
Linked List, Two Pointers, Stack

Asked at TCS in the last 3 months

1.
Reverse Linked List · EasyAsked recently
Three pointers: prev, current, next. Point current back to prev and move all three forward. Know the recursive version too.
Linked List, Recursion
2.
Balanced Binary Tree · EasyAsked recently
Return the height from each subtree, or -1 the moment one side is off by more than 1. One pass, not a height call per node.
Tree, DFS
3.
Find Peak Element · MediumAsked recently
Binary search: if mid is smaller than mid+1, a peak is on the right; otherwise it's at mid or on the left.
Array, Binary Search
4.
Kth Largest Element in an Array · MediumAsked recently
Min-heap of size k: the top is your answer at the end. Quickselect is faster on average if they push for it.
Array, Divide and Conquer, Sorting
5.
Kth Smallest Element in a BST · MediumAsked recently
Inorder traversal of a BST gives sorted order. Stop at the kth node you visit.
Tree, DFS, BST

TCS Ninja coding questions

15 questions · 100% Easy, 0% Medium, 0% Hard

1.
Single Number · Easy
XOR everything. Pairs cancel out and the single number is what's left.
Bit Manipulation
2.
Fizz Buzz · Easy
Check 15 first, then 3, then 5. It's a warm-up; get it right in one go and move on.
Math, String
3.
Reverse Integer · Easy
Pop digits with % 10 and build the result, but check for 32-bit overflow before every multiply.
Math
4.
Climbing Stairs · Easy
It's Fibonacci in disguise: ways(n) = ways(n-1) + ways(n-2). Two variables are enough.
DP
5.
Palindrome Linked List · Easy
Find the middle with slow and fast pointers, reverse the second half, then compare both halves.
Linked List, Two Pointers
6.
Merge Sorted Array · Easy
Two Pointers
7.
Valid Anagram · Easy
String, Hash Table
8.
Happy Number · Easy
Keep summing the squares of digits. To catch the loop, use a set or slow and fast pointers.
Math, Hash Table
9.
Remove Duplicates from Sorted Array · Easy
Two Pointers
10.
Remove Duplicates from Sorted List · Easy
Walk the list and skip the next node while it has the same value. No extra memory.
Linked List

See all 15 TCS Ninja questions (pick it as a free company)

TCS Digital coding questions

16 questions · 38% Easy, 62% Medium, 0% Hard

1.
Maximum Depth of Binary Tree · Easy
One line of recursion: 1 + max(depth of left, depth of right). BFS level by level works too.
Tree, DFS
2.
Find Minimum in Rotated Sorted Array · Medium
Binary search against the right end: if mid is bigger than the right value, the minimum is on the right side.
Binary Search
3.
Sort Colors · Medium
Dutch national flag: three pointers for the 0s, the current element and the 2s. One pass.
Two Pointers, Array
4.
Symmetric Tree · Easy
Compare the left subtree with the mirror of the right: left.left with right.right, and left.right with right.left.
Tree, DFS
5.
Majority Element II · Medium
Same voting idea, but with two candidates, since at most two numbers can appear more than n/3 times. Verify the counts at the end.
Array
6.
Same Tree · Easy
Recursively compare: both empty, or same value with the same left and right subtrees.
Tree, DFS
7.
Search Insert Position · Easy
Plain lower-bound binary search. When the loop ends, left is the answer.
Binary Search
8.
Set Matrix Zeroes · Medium
Use the first row and column as markers to get O(1) space. Remember separately whether they had a zero themselves.
Matrix
9.
Product of Array Except Self · Medium
Prefix products from the left, suffix products from the right, multiply them. No division needed.
Array
10.
Remove Element · Easy
Two pointers: copy every value that isn't the target to the front. The count of copies is the answer.
Two Pointers

See all 16 TCS Digital questions (pick it as a free company)

TCS Prime coding questions

13 questions · 0% Easy, 38% Medium, 62% Hard

1.
Maximum Product Subarray · Medium
Track both the max and the min product ending here, because a negative number flips them.
DP
2.
Edit Distance · Hard
Classic 2D DP. dp[i][j] is the cost to turn the first i letters into the first j: take the min of insert, delete and replace.
DP
3.
First Missing Positive · Hard
Array
4.
Longest Palindromic Substring · Medium
String, DP
5.
Top K Frequent Elements · Medium
Count with a hash map, then use a min-heap of size k, or bucket sort by frequency for O(n).
Heap
6.
Best Time to Buy and Sell Stock IV · Hard
DP over (day, transactions left, holding or not). If k is bigger than n/2 it turns into the unlimited-trades version.
DP
7.
Word Break · Medium
dp[i] is true if some earlier dp[j] is true and s[j:i] is in the dictionary. Put the words in a set.
DP
8.
Longest Valid Parentheses · Hard
Stack of indices with a -1 at the bottom as a base. The length is the current index minus the index on top of the stack.
Stack, DP
9.
Minimum Window Substring · Hard
Sliding window with a count map. Grow the right side until the window is valid, then shrink the left as far as you can.
Sliding Window
10.
Course Schedule II · Medium
Topological sort. Kahn's algorithm with in-degrees is the easiest to explain; if you can't take every course, there's a cycle.
Graph, Topological Sort

See all 13 TCS Prime questions (pick it as a free company)

If you only have a week

Arrays are in more than half of the main TCS list. Do those first.
Going for Digital or Prime? Ninja-level questions won't be enough. Look at the Prime list below: Edit Distance, Maximum Product Subarray, First Missing Positive. That is the level.
DP shows up a lot more in Digital and Prime than in Ninja. Climbing Stairs is a fine warm-up, but don't stop there.
Questions marked "Asked recently" showed up in the last 3 months. Give them a little extra time.

From students who sat the TCS test

Sat the TCS test recently? Tell us which questions you got and we will add them here with your name. Share your experience

Common questions

What coding questions does TCS ask?

Right now the most common ones are Best Time to Buy and Sell Stock, Container With Most Water and Two Sum. The top 10 above is sorted by how recently and how often each one was asked.

Is the TCS coding round hard?

Mostly not. In this list, 43% of the questions are Easy, 47% Medium and 10% Hard.

Which topics should I study for TCS?

Start with Array (58%), Hash Table (21%) and String (21%). Together they cover most of the TCS list.

Is this the official TCS question bank?

No. Nobody outside TCS has that. This list comes from LeetCode company tags, where candidates report the questions they got. Treat it as the best public signal, not a guarantee.

How do I get the full TCS list?

How this page is made

The question list comes from the company tags on LeetCode, where candidates report the questions they were asked. We sort it by how recently and how often each question came up, and refresh it from the source regularly (this page: 3 Nov 2026). Every question links to the original problem; we don't copy problem statements. The one-line tricks, the topic breakdown and the tips are written and checked by Aayush Kumar Gupta and the Tauzand team. If you spot a mistake, tell us.