SDE
Interview Prep
How much DSA do you need for an internship?
How much DSA you need for an internship depends on the company. For an SDE internship at a large product company, you need enough to pass a timed coding test: Amazon's intern assessment gives about 70 minutes for coding. Arrays, hashmaps, strings and sorting come up most. Where DSA isn't tested, projects matter more.
What Amazon asks of SDE interns
Amazon publishes its requirements, which makes it a useful benchmark. Its 6-month SDE internship in Bengaluru, starting January 2027, lists "Experience with data structure implementation, basic algorithm development, and/or object-oriented design principles" under basic qualifications (Amazon Jobs).
That's "basic", and it sits next to "at least one general-purpose programming language such as Java, Python, C++, C#, Go, Rust, or TypeScript". The same posting lists "demonstrated project experience" as a preferred qualification.
The online assessment is short. Amazon's prep page for student SDE roles puts the intern version at about 90 minutes in total: a coding assessment averaging 70 minutes, a Workstyles assessment of about 15 minutes and a 5-minute feedback survey (Amazon Jobs).
Two rules on that page change how you should practise. You may use "publicly accessible online resources", such as Java or C++ standard library documentation, but you mustn't copy and paste, and "Your browser usage is logged."
Which DSA topics come up most often
HackerRank's prep kit shows what share of companies test each topic. Use it to decide what to learn first, not to skip anything entirely.
| Topic | Share of companies testing it |
|---|---|
| Arrays | 70% |
| Dictionaries and hashmaps | 40% |
| Sorting | 40% |
| String manipulation | 40% |
| Greedy algorithms | 31% |
| Search | 30% |
| Dynamic programming | 27% |
| Stacks and queues | 17% |
| Graphs | 15% |
| Trees | 12% |
| Linked lists | 8% |
| Recursion and backtracking | 5% |
Source: HackerRank Interview Preparation Kit.
Start with the top four rows. Linked lists and recursion sit near the bottom, so don't spend your first month on them just because textbooks open with them.
The hashmap pattern alone turns a lot of slow answers into fast ones. Here's the classic case, finding two numbers that add up to a target:
def two_sum(nums, target):
seen = {} # value -> index
for i, n in enumerate(nums):
if target - n in seen:
return [seen[target - n], i]
seen[n] = i
return []Checking every pair takes O(n²) time. Remembering what you've seen in a dictionary takes one pass, O(n). Being able to say that out loud, and why, is what "reason about complexity" means in an interview.
How much DSA is enough for each kind of internship
Read the posting's basic qualifications before you plan anything. If it names data structures or algorithms, expect a timed coding test; if it names only a framework and asks for a GitHub link, spend more of your time on projects.
| Internship | What the posting or prep page asks | How to split your prep |
|---|---|---|
| SDE intern at a large product company (Amazon example) | Data structures, basic algorithms or OOP; a roughly 70-minute coding test | Mostly DSA, plus one project you can defend |
| Front-end intern at Amazon | "Data structures and algorithms" alongside "Front end tech (JavaScript/CSS/HTML)" in one round of two interviews (Amazon Jobs) | Half DSA, half JavaScript and CSS |
| Web or app intern where the posting lists a framework and a portfolio | Varies; check the posting | Mostly projects, with the top four DSA topics as a safety net |
A front-end role at a large company still means DSA practice. What changes is the rest of the interview. If you haven't picked a side yet, frontend vs backend developer has a rule based on what you already know.
A 6-week DSA plan for an internship
Six weeks covers the high-frequency topics if you already know one language. Do two problems a day, and time one of them.
| Week | Topics | Finish the week able to |
|---|---|---|
| 1 | Arrays, hashmaps | Solve two-sum and frequency-count problems in O(n) |
| 2 | Strings, sorting | Explain why a sort costs O(n log n) and when you can avoid it |
| 3 | Binary search, greedy | Spot when a sorted input lets you search in O(log n) |
| 4 | Stacks, queues, recursion | Trace a recursive call by hand without running it |
| 5 | Trees, graphs (BFS and DFS) | Traverse a grid or tree both ways and say which fits |
| 6 | Dynamic programming basics, full mock tests | Finish a 70-minute timed test in the language you'll use |
Keep a log of every problem you couldn't solve and why. Redo those at the end of each week, because the second attempt is where the pattern sticks.
Practise under the same conditions as the test
Practise in the language you'll use on test day and in a plain editor. Amazon's own advice is to "Review and practice the coding language you plan to use", and it offers an unscored practice test with two questions.
Since the real test allows public documentation, learn where things live in your language's docs: how to sort with a custom key, which collection gives constant-time lookups. Finding those in 20 seconds is a skill worth practising, and it saves you from writing a helper you didn't need.
If you get stuck, Amazon's page says to skip the problem and come back to it. Practise doing exactly that in your mocks, so you don't spend 40 minutes on one question.
Why projects still matter alongside DSA
DSA gets you through the screen; projects give you something to talk about once you're through it. Amazon's student SDE page says interviewers "will ask about past experiences and specific situations" (Amazon Jobs), and its intern posting prefers "demonstrated project experience".
Have one project you can explain for two minutes: the problem, one trade-off and one bug you fixed. The frontend projects for your resume post has a structure for that walkthrough that works for any stack.
Where DevIt's SDE track fits
DevIt's Software Development Engineer (SDE) Internship gives its second week to data structures and algorithms, and one of its listed outcomes is to "reason about Big-O complexity". The 1-month plan has 3 projects, 1 quiz and 2 coding exercises, which are graded automatically.
That's a structured start, not a replacement for six weeks of timed practice. It's a paid training internship with no stipend; on 18 October 2026 the track page listed the 1-month plan at ₹299. The internships page lists the other tracks.
Frequently asked questions
- How many LeetCode problems are enough for an internship?
- No company publishes a number. Aim to solve unseen easy and medium problems on the top topics within the time limit, and explain the complexity of each answer. That matters more than the total count.
- Which language is best for DSA interviews?
- The one you write fastest without looking things up. Amazon's intern posting asks for any general-purpose language and names Java, Python, C++, C#, Go, Rust and TypeScript as examples.
- Can I get an internship without knowing DSA?
- Yes, if the role doesn't test it. Check the posting's basic qualifications: if they list only a framework and a portfolio, put your time into projects. For SDE roles at large product companies, plan for a timed coding test.
- When should I start preparing DSA for internships?
- At least six weeks before you plan to apply, and earlier if you're still learning your first language. Amazon sends its online assessment after an application, so you won't get extra time once you've applied.
Amazon pages, HackerRank topic data and DevIt track details checked 18 October 2026.