Top 50 Google LeetCode Hash Table Questions (2026) – Must Practice 🚀

Practice the most frequently asked Hash Table (Hashing) LeetCode questions in Google interviews. Learn key patterns like frequency counting, maps, and set-based problems.

#Interview Questions

Sl.No	Question	Difficulty	Frequency	LeetCode Link
1	Two Sum	EASY	100.00%	Solve
2	Online Election	MEDIUM	94.50%	Solve
3	Stock Price Fluctuation	MEDIUM	86.60%	Solve
4	Longest Substring Without Repeating Characters	MEDIUM	82.60%	Solve
5	LRU Cache	MEDIUM	79.20%	Solve
6	Group Anagrams	MEDIUM	78.90%	Solve
7	Letter Combinations of a Phone Number	MEDIUM	68.20%	Solve
8	Longest Consecutive Sequence	MEDIUM	66.20%	Solve
9	Roman to Integer	EASY	66.10%	Solve
10	Valid Sudoku	MEDIUM	61.10%	Solve
11	Word Break	MEDIUM	60.60%	Solve
12	First Missing Positive	HARD	59.10%	Solve
13	Set Matrix Zeroes	MEDIUM	58.70%	Solve
14	Minimum Window Substring	HARD	54.80%	Solve
15	Word Break II	HARD	53.30%	Solve
16	Integer to Roman	MEDIUM	52.20%	Solve
17	Rank Teams by Votes	MEDIUM	51.60%	Solve
18	Valid Anagram	EASY	51.40%	Solve
19	Detect Squares	MEDIUM	50.00%	Solve
20	Word Ladder	HARD	44.80%	Solve
21	Isomorphic Strings	EASY	43.10%	Solve
22	Sudoku Solver	HARD	42.70%	Solve
23	Missing Number	EASY	42.20%	Solve
24	Contains Duplicate II	EASY	42.20%	Solve
25	Copy List with Random Pointer	MEDIUM	39.20%	Solve
26	Clone Graph	MEDIUM	38.60%	Solve
27	Number of Islands II	HARD	38.60%	Solve
28	First Unique Character in a String	EASY	37.90%	Solve
29	Number of Substrings Containing All Three Characters	MEDIUM	37.90%	Solve
30	Binary Subarrays With Sum	MEDIUM	37.50%	Solve
31	Find Original Array From Doubled Array	MEDIUM	37.50%	Solve
32	Maximum Number of Ways to Partition an Array	HARD	37.50%	Solve
33	Rank Transform of an Array	EASY	37.50%	Solve
34	Find the Difference of Two Arrays	EASY	37.50%	Solve
35	Check If N and Its Double Exist	EASY	37.50%	Solve
36	Design a Number Container System	MEDIUM	37.50%	Solve
37	Sender With Largest Word Count	MEDIUM	37.50%	Solve
38	Tuple with Same Product	MEDIUM	37.50%	Solve
39	Unique Length-3 Palindromic Subsequences	MEDIUM	37.50%	Solve
40	Group Shifted Strings	MEDIUM	35.40%	Solve
41	Linked List Cycle	EASY	35.20%	Solve
42	Construct Binary Tree from Preorder and Inorder Traversal	MEDIUM	33.60%	Solve
43	Substring with Concatenation of All Words	HARD	32.60%	Solve
44	Fraction to Recurring Decimal	MEDIUM	30.60%	Solve
45	Strobogrammatic Number	EASY	25.10%	Solve
46	Longest Substring with At Most Two Distinct Characters	MEDIUM	25.10%	Solve
47	Array of Doubled Pairs	MEDIUM	25.00%	Solve
48	Minimum Operations to Reduce X to Zero	MEDIUM	25.00%	Solve
49	Alphabet Board Path	MEDIUM	25.00%	Solve
50	Minimum Operations to Make a Subsequence	HARD	25.00%	Solve

Top 50 Google LeetCode Hash Table Questions (2026) – Must Practice 🚀

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