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TCS interview questions

The most frequent LeetCode problems tagged to TCS. This is a data-only page. For process and behavioral prep, use the coding guide and behavioral guide.

Based on 98 distinct problems tagged to TCS in the last 6 months (36 in the last 30 days, 65 in the last 3 months, 243 all-time) across two open datasets of LeetCode company tags. Tags are user-reported, so treat frequency as a signal, not a promise.

Difficulty mix (last 6 months): Medium 49%, Easy 45%, Hard 6%

Most tagged topics (share of problems): Array 65%, Hash Table 26%, String 20%, Two Pointers 19%, Sorting 18%, Math 15%, Dynamic Programming 11%, Binary Search 10%, Recursion 8%, Stack 8%

Most frequent problems

Ranked by frequency, weighted toward the last 30 days. Classics like Two Sum sit near the top of almost every company's list because users tag them everywhere. Solve those fast. The signature list below is more specific to this company.

# Problem Difficulty Last seen Topics
1 Container With Most Water Medium 30 days Array, Two Pointers, Greedy
2 First Missing Positive Hard 30 days Array, Hash Table
3 Two Sum Easy 30 days Array, Hash Table
4 Rank Transform of an Array Easy 30 days Array, Hash Table, Sorting
5 Integer to Roman Medium 30 days Hash Table, Math, String
6 Roman to Integer Easy 30 days Hash Table, Math, String
7 Longest Palindromic Substring Medium 30 days Two Pointers, String, Dynamic Programming, Manacher
8 Fibonacci Number Easy 30 days Math, Dynamic Programming, Recursion, Memoization
9 First Unique Character in a String Easy 30 days Hash Table, String, Queue, Counting
10 Palindrome Number Easy 30 days Math
11 Merge Sorted Array Easy 30 days Array, Two Pointers, Sorting
12 Remove Duplicates from Sorted Array Easy 30 days Array, Two Pointers
13 Longest Consecutive Sequence Medium 30 days Array, Hash Table, Union-Find
14 Longest Substring Without Repeating Characters Medium 30 days Hash Table, String, Sliding Window
15 Largest Rectangle in Histogram Hard 30 days Array, Stack, Monotonic Stack, Range Minimum/Maximum Query
16 Rotate Array Medium 30 days Array, Math, Two Pointers
17 Valid Anagram Easy 30 days Hash Table, String, Sorting
18 Contains Duplicate II Easy 30 days Array, Hash Table, Sliding Window
19 Kth Smallest Element in a BST Medium 30 days Tree, Depth-First Search, Binary Search Tree, Binary Tree
20 Sort Colors Medium 30 days Array, Two Pointers, Sorting, Quicksort
21 Maximum Product of Three Numbers Easy 30 days Array, Math, Sorting
22 Best Time to Buy and Sell Stock Easy 30 days Array, Dynamic Programming
23 Reverse String Easy 30 days Two Pointers, String
24 Group Anagrams Medium 30 days Array, Hash Table, String, Sorting
25 Maximum Average Subarray I Easy 30 days Array, Sliding Window
26 Two Sum II - Input Array Is Sorted Medium 30 days Array, Two Pointers, Binary Search
27 Palindrome Linked List Easy 30 days Linked List, Two Pointers, Stack, Recursion
28 Search Insert Position Easy 30 days Array, Binary Search
29 Find Peak Element Medium 30 days Array, Binary Search
30 Find Missing Elements Easy 30 days Array, Hash Table, Sorting
31 Find the Peaks Easy 30 days Array, Enumeration
32 Permutation in String Medium 30 days Hash Table, Two Pointers, String, Sliding Window
33 Valid Palindrome Easy 30 days Two Pointers, String
34 Top K Frequent Words Medium 30 days Array, Hash Table, String, Trie
35 Peak Index in a Mountain Array Medium 30 days Array, Binary Search, Ternary Search
36 Maximum Subarray Medium 3 months Array, Divide and Conquer, Dynamic Programming
37 Minimum Number of Operations to Reinitialize a Permutation Medium 30 days Array, Math, Simulation
38 Toeplitz Matrix Easy 3 months Array, Matrix
39 Move Zeroes Easy 3 months Array, Two Pointers
40 Longest Common Prefix Easy 3 months Array, String, Trie

Signature problems

Problems where TCS accounts for a large share of all recent tags across companies. These are the most TCS-specific questions in the data.

# Problem Difficulty Last seen Topics
1 First Missing Positive Hard 30 days Array, Hash Table
2 Rank Transform of an Array Easy 30 days Array, Hash Table, Sorting
3 Toeplitz Matrix Easy 3 months Array, Matrix
4 Find Missing Elements Easy 30 days Array, Hash Table, Sorting
5 Find the Peaks Easy 30 days Array, Enumeration
6 Maximum Total Subarray Value I Medium 3 months Array, Greedy
7 Minimum Number of Operations to Reinitialize a Permutation Medium 30 days Array, Math, Simulation
8 Minimum Depth of Binary Tree Easy 3 months Tree, Depth-First Search, Breadth-First Search, Binary Tree
9 Maximum Ice Cream Bars Medium 3 months Array, Greedy, Sorting, Counting Sort
10 Smallest Range Covering Elements from K Lists Hard 3 months Array, Hash Table, Greedy, Sliding Window
11 Count Odd Numbers in an Interval Range Easy 6 months Math

Sources

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