Problem database last updated: June 20, 2025
26 problems · 13 Easy, 12 Medium, 1 Hard · Ranked #74 of 458
13 Easy
50% · avg 23%
12 Medium
46% · avg 59%
1 Hard
4% · avg 18%
Based on 26 reported problems, Deloitte interviews are easier than average - only 4% Hard compared to 18% across all companies.
Compared to the industry average, Deloitte puts unusual emphasis on database (19.2% of problems, 17.1x the industry average), divide-and-conquer (11.5% of problems, 2.8x the industry average). If you're short on time, these are the categories to double down on.
The most common topics are array (42.3%), string (23.1%), dynamic-programming (23.1%), database (19.2%). Problems below are sorted by frequency, the ones at the top are asked most often.
| Problem | Difficulty | Frequency | Topics | |
|---|---|---|---|---|
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 |
Merge k Sorted Lists You are given an array of k linked-lists lists, each linked-list is sorted in ascending order. | Hard | Very Likely | linked-listdivide-and-conquerheap-priority-queue | Solve |
Valid Parentheses Given a string s containing just the characters '(', ')', '{', '}', '[' and ']', determine if the input string is valid. | Easy | Very Likely | stringstack | Solve |
Container With Most Water You are given an integer array height of length n. There are n vertical lines drawn such that the two endpoints of the ith line are (i, 0) and (i, height[i]). | Medium | Very Likely | arraytwo-pointersgreedy | Solve |
Palindrome Number Given an integer x, return true if x is a palindrome, and false otherwise. | Easy | Very Likely | math | Solve |
Longest Palindromic Substring Given a string s, return the longest palindromic substring in s. | Medium | Very Likely | two-pointersstringdynamic-programming | Solve |
Second Highest Salary Table: Employee | Medium | Very Likely | database | Solve |
Managers with at Least 5 Direct Reports Table: Employee | Medium | Likely | database | Solve |
Climbing Stairs You are climbing a staircase. It takes n steps to reach the top. | Easy | Likely | mathdynamic-programmingmemoization | Solve |
Rising Temperature Table: Weather | Easy | Likely | database | Solve |
Reverse Integer Given a signed 32-bit integer x, return x with its digits reversed. If reversing x causes the value to go outside the signed 32-bit integer range [-231, 231 - 1... | Medium | Likely | math | Solve |
Majority Element Given an array nums of size n, return the majority element. | Easy | Likely | arrayhash-tabledivide-and-conquer | Solve |
Kth Largest Element in an Array Given an integer array nums and an integer k, return the kth largest element in the array. | Medium | Likely | arraydivide-and-conquersorting | Solve |
Coin Change You are given an integer array coins representing coins of different denominations and an integer amount representing a total amount of money. | Medium | Likely | arraydynamic-programmingbreadth-first-search | Solve |
Reverse Linked List Given the head of a singly linked list, reverse the list, and return the reversed list. | Easy | Likely | linked-listrecursion | Solve |
Pascal's Triangle Given an integer numRows, return the first numRows of Pascal's triangle. | Easy | Likely | arraydynamic-programming | Solve |
Edit Distance Given two strings word1 and word2, return the minimum number of operations required to convert word1 to word2. | Medium | Likely | stringdynamic-programming | Solve |
Max Consecutive Ones Given a binary array nums, return the maximum number of consecutive 1's in the array. | Easy | Likely | array | Solve |
Find Customer Referee Table: Customer | Easy | Likely | database | Solve |
Longest Substring Without Repeating Characters Given a string s, find the length of the longest substring without duplicate characters. | Medium | Likely | hash-tablestringsliding-window | Solve |
Merge Intervals Given an array of intervals where intervals[i] = [starti, endi], merge all overlapping intervals, and return an array of the non-overlapping intervals that cove... | Medium | Likely | arraysorting | Solve |
Best Time to Buy and Sell Stock You are given an array prices where prices[i] is the price of a given stock on the ith day. | Easy | Likely | arraydynamic-programming | Solve |
Minimum Time to Repair Cars You are given an integer array ranks representing the ranks of some mechanics. ranksi is the rank of the ith mechanic. A mechanic with a rank r can repair n car... | Medium | Likely | arraybinary-search | Solve |
Article Views I Table: Views | Easy | Likely | database | Solve |
Longest Common Prefix Write a function to find the longest common prefix string amongst an array of strings. | Easy | Likely | arraystringtrie | Solve |
Reverse Words in a String Given an input string s, reverse the order of the words. | Medium | Likely | two-pointersstring | Solve |
Two Sum
SolveGiven an array of integers nums and an integer target, return the indices of the two numbers that add up to target.
Merge k Sorted Lists
SolveYou are given an array of k linked-lists lists, each linked-list is sorted in ascending order.
Valid Parentheses
SolveGiven a string s containing just the characters '(', ')', '{', '}', '[' and ']', determine if the input string is valid.
Container With Most Water
SolveYou are given an integer array height of length n. There are n vertical lines drawn such that the two endpoints of the ith line are (i, 0) and (i, height[i]).
Palindrome Number
SolveGiven an integer x, return true if x is a palindrome, and false otherwise.
Longest Palindromic Substring
SolveGiven a string s, return the longest palindromic substring in s.
Climbing Stairs
SolveYou are climbing a staircase. It takes n steps to reach the top.
Reverse Integer
SolveGiven a signed 32-bit integer x, return x with its digits reversed. If reversing x causes the value to go outside the signed 32-bit integer range [-231, 231 - 1...
Majority Element
SolveGiven an array nums of size n, return the majority element.
Kth Largest Element in an Array
SolveGiven an integer array nums and an integer k, return the kth largest element in the array.
Coin Change
SolveYou are given an integer array coins representing coins of different denominations and an integer amount representing a total amount of money.
Reverse Linked List
SolveGiven the head of a singly linked list, reverse the list, and return the reversed list.
Pascal's Triangle
SolveGiven an integer numRows, return the first numRows of Pascal's triangle.
Edit Distance
SolveGiven two strings word1 and word2, return the minimum number of operations required to convert word1 to word2.
Max Consecutive Ones
SolveGiven a binary array nums, return the maximum number of consecutive 1's in the array.
Longest Substring Without Repeating Characters
SolveGiven a string s, find the length of the longest substring without duplicate characters.
Merge Intervals
SolveGiven an array of intervals where intervals[i] = [starti, endi], merge all overlapping intervals, and return an array of the non-overlapping intervals that cove...
Best Time to Buy and Sell Stock
SolveYou are given an array prices where prices[i] is the price of a given stock on the ith day.
Minimum Time to Repair Cars
SolveYou are given an integer array ranks representing the ranks of some mechanics. ranksi is the rank of the ith mechanic. A mechanic with a rank r can repair n car...
Longest Common Prefix
SolveWrite a function to find the longest common prefix string amongst an array of strings.
Reverse Words in a String
SolveGiven an input string s, reverse the order of the words.
Frequency scores are based on crowdsourced interview reports. A higher score means the problem has been reported more often in recent Deloitte interviews.
Very Likely
75-100%
Likely
50-74%
Sometimes
25-49%
Rare
0-24%
Deloitte interviews focus heavily on array, string, dynamic-programming 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. Deloitte 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.
Deloitte has been reported to ask 26 distinct coding problems. The most common topics are array, string, dynamic-programming. 13 are Easy difficulty, 12 are Medium, and 1 are Hard. Problems are sorted by frequency - the ones at the top are asked most often.
Based on 26 reported problems, Deloitte interviews are easier than average - only 4% Hard compared to 18% across all companies. 46% of questions are Medium difficulty. Focus on the high-frequency Medium problems first, then work through the Hard ones.
Start with the highest-frequency problems listed on this page. Focus on the core topics: array, string, dynamic-programming. 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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