Problem database last updated: June 20, 2025
11 problems · 4 Easy, 3 Medium, 4 Hard · Ranked #135 of 458
4 Easy
36% · avg 23%
3 Medium
27% · avg 59%
4 Hard
36% · avg 18%
Based on 11 reported problems, Jane Street interviews are significantly harder than average - 36% Hard vs 18% across all companies.
Compared to the industry average, Jane Street puts unusual emphasis on simulation (36.4% of problems, 8.4x the industry average), trie (18.2% of problems, 6.9x the industry average), design (18.2% of problems, 3.1x the industry average). If you're short on time, these are the categories to double down on.
The most common topics are array (72.7%), string (54.5%), simulation (36.4%), hash-table (18.2%). Problems below are sorted by frequency, the ones at the top are asked most often.
| Problem | Difficulty | Frequency | Topics | |
|---|---|---|---|---|
Count Common Words With One Occurrence Given two string arrays words1 and words2, return the number of strings that appear exactly once in each of the two arrays. | Easy | Very Likely | arrayhash-tablestring | Solve |
Walking Robot Simulation A robot on an infinite XY-plane starts at point (0, 0) facing north. The robot receives an array of integers commands, which represents a sequence of moves that... | Medium | Very Likely | arrayhash-tablesimulation | Solve |
Minimum Time to Make Array Sum At Most x You are given two 0-indexed integer arrays nums1 and nums2 of equal length. Every second, for all indices 0 <= i < nums1.length, value of nums1[i] is incremente... | Hard | Very Likely | arraydynamic-programmingsorting | Solve |
Add Two Integers Given two integers num1 and num2, return the sum of the two integers. | Easy | Very Likely | math | Solve |
Stream of Characters Design an algorithm that accepts a stream of characters and checks if a suffix of these characters is a string of a given array of strings words. | Hard | Likely | arraystringdesign | Solve |
Add Strings Given two non-negative integers, num1 and num2 represented as string, return the sum of num1 and num2 as a string. | Easy | Likely | mathstringsimulation | Solve |
Design a Text Editor Design a text editor with a cursor that can do the following: | Hard | Likely | linked-liststringstack | Solve |
Number of Orders in the Backlog You are given a 2D integer array orders, where each orders[i] = [pricei, amounti, orderTypei] denotes that amounti orders have been placed of type orderTypei at... | Medium | Likely | arrayheap-priority-queuesimulation | Solve |
Evaluate Division You are given an array of variable pairs equations and an array of real numbers values, where equations[i] = [Ai, Bi] and values[i] represent the equation Ai /... | Medium | Likely | arraystringdepth-first-search | Solve |
Trapping Rain Water Given n non-negative integers representing an elevation map where the width of each bar is 1, compute how much water it can trap after raining. | Hard | Likely | arraytwo-pointersdynamic-programming | Solve |
Longest Common Prefix Write a function to find the longest common prefix string amongst an array of strings. | Easy | Likely | arraystringtrie | Solve |
Count Common Words With One Occurrence
SolveGiven two string arrays words1 and words2, return the number of strings that appear exactly once in each of the two arrays.
Walking Robot Simulation
SolveA robot on an infinite XY-plane starts at point (0, 0) facing north. The robot receives an array of integers commands, which represents a sequence of moves that...
Minimum Time to Make Array Sum At Most x
SolveYou are given two 0-indexed integer arrays nums1 and nums2 of equal length. Every second, for all indices 0 <= i < nums1.length, value of nums1[i] is incremente...
Add Two Integers
SolveGiven two integers num1 and num2, return the sum of the two integers.
Stream of Characters
SolveDesign an algorithm that accepts a stream of characters and checks if a suffix of these characters is a string of a given array of strings words.
Add Strings
SolveGiven two non-negative integers, num1 and num2 represented as string, return the sum of num1 and num2 as a string.
Design a Text Editor
SolveDesign a text editor with a cursor that can do the following:
Number of Orders in the Backlog
SolveYou are given a 2D integer array orders, where each orders[i] = [pricei, amounti, orderTypei] denotes that amounti orders have been placed of type orderTypei at...
Evaluate Division
SolveYou are given an array of variable pairs equations and an array of real numbers values, where equations[i] = [Ai, Bi] and values[i] represent the equation Ai /...
Trapping Rain Water
SolveGiven n non-negative integers representing an elevation map where the width of each bar is 1, compute how much water it can trap after raining.
Longest Common Prefix
SolveWrite a function to find the longest common prefix string amongst an array of strings.
Frequency scores are based on crowdsourced interview reports. A higher score means the problem has been reported more often in recent Jane Street interviews.
Very Likely
75-100%
Likely
50-74%
Sometimes
25-49%
Rare
0-24%
Jane Street interviews focus heavily on array, string, simulation 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. Jane Street 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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Jane Street has been reported to ask 11 distinct coding problems. The most common topics are array, string, simulation. 4 are Easy difficulty, 3 are Medium, and 4 are Hard. Problems are sorted by frequency - the ones at the top are asked most often.
Based on 11 reported problems, Jane Street interviews are significantly harder than average - 36% Hard vs 18% across all companies. 27% 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, simulation. 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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