Problem database last updated: June 20, 2025
12 problems · 5 Easy, 6 Medium, 1 Hard · Ranked #122 of 458
5 Easy
42% · avg 23%
6 Medium
50% · avg 59%
1 Hard
8% · avg 18%
Based on 12 reported problems, Mastercard interviews are in line with industry averages - 8% Hard vs 18% overall.
Compared to the industry average, Mastercard puts unusual emphasis on greedy (25% of problems, 3x the industry average). If you're short on time, these are the categories to double down on.
The most common topics are array (66.7%), string (33.3%), dynamic-programming (25%), greedy (25%). 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 |
Valid Parentheses Given a string s containing just the characters '(', ')', '{', '}', '[' and ']', determine if the input string is valid. | Easy | Very Likely | stringstack | Solve |
Valid Anagram Given two strings s and t, return true if t is an anagram of s, and false otherwise. | Easy | Very Likely | hash-tablestringsorting | 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 | Very Likely | arraydynamic-programming | 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 | Very Likely | arraydynamic-programmingbreadth-first-search | Solve |
Subsets Given an integer array nums of unique elements, return all possible subsets (the power set). | Medium | Very Likely | arraybacktrackingbit-manipulation | Solve |
Gas Station There are n gas stations along a circular route, where the amount of gas at the ith station is gas[i]. | Medium | Very Likely | arraygreedy | Solve |
Rotate Image You are given an n x n 2D matrix representing an image, rotate the image by 90 degrees (clockwise). | Medium | Very Likely | arraymathmatrix | Solve |
Fizz Buzz Given an integer n, return a string array answer (1-indexed) where: | Easy | Very Likely | mathstringsimulation | Solve |
Longest Palindromic Substring Given a string s, return the longest palindromic substring in s. | Medium | Very Likely | two-pointersstringdynamic-programming | Solve |
Candy There are n children standing in a line. Each child is assigned a rating value given in the integer array ratings. | Hard | Very Likely | arraygreedy | 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 |
Two Sum
SolveGiven an array of integers nums and an integer target, return the indices of the two numbers that add up to target.
Valid Parentheses
SolveGiven a string s containing just the characters '(', ')', '{', '}', '[' and ']', determine if the input string is valid.
Valid Anagram
SolveGiven two strings s and t, return true if t is an anagram of s, and false otherwise.
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.
Coin Change
SolveYou are given an integer array coins representing coins of different denominations and an integer amount representing a total amount of money.
Subsets
SolveGiven an integer array nums of unique elements, return all possible subsets (the power set).
Gas Station
SolveThere are n gas stations along a circular route, where the amount of gas at the ith station is gas[i].
Rotate Image
SolveYou are given an n x n 2D matrix representing an image, rotate the image by 90 degrees (clockwise).
Fizz Buzz
SolveGiven an integer n, return a string array answer (1-indexed) where:
Longest Palindromic Substring
SolveGiven a string s, return the longest palindromic substring in s.
Candy
SolveThere are n children standing in a line. Each child is assigned a rating value given in the integer array ratings.
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]).
Frequency scores are based on crowdsourced interview reports. A higher score means the problem has been reported more often in recent Mastercard interviews.
Very Likely
75-100%
Likely
50-74%
Sometimes
25-49%
Rare
0-24%
Mastercard 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. Mastercard 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.
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Mastercard has been reported to ask 12 distinct coding problems. The most common topics are array, string, dynamic-programming. 5 are Easy difficulty, 6 are Medium, and 1 are Hard. Problems are sorted by frequency - the ones at the top are asked most often.
Based on 12 reported problems, Mastercard interviews are in line with industry averages - 8% Hard vs 18% overall. 50% 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.
Simulate a real Mastercard coding interview with an AI interviewer. Get a scorecard with specific feedback on your problem-solving, code quality, and communication.
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