You cannot cram HackWithInfy, but you can prepare it efficiently. Round 1 is won by solving the easy and medium problems completely and squeezing partial marks from the hard one — that is the "2.5 problems" SP threshold participants keep quoting. A twelve-week plan that respects that fact is below; compress it to eight if you already do competitive programming.
Twelve-week plan
- Weeks 1–2 — Language and I/O. Pick C++, Java or Python and stay with it. Practise reading multiple test cases from standard input, printing exact output, 64-bit integers and fast I/O. Solve 20 array/hashing problems without any algorithms.
- Weeks 3–5 — Core patterns. Prefix sums, two pointers, sliding window, sorting with custom keys, binary search on the answer, heaps, sieve and modular arithmetic. Redo Dish Selection and K Closest Points until you can write them blind.
- Weeks 6–8 — Dynamic programming. This is the deciding topic. 1-D DP (house robber, LIS), 2-D DP (grid paths, LCS/edit distance), Kadane and its variants, state-transition DP. One problem a day, always with the recurrence written before code.
- Weeks 9–10 — Graphs and trees. BFS/DFS, shortest paths, connected components, DP on DAGs; basic tree traversals and range queries. This is where the Round 1 hard and Round 2 problems live.
- Week 11 — Timed sets. Take Infosys's official four-problem sample set in one three-hour sitting, then two more self-timed three-problem sets from past HackWithInfy or CodeVita problems. Upsolve everything you missed.
- Week 12 — Mock test and taper. Do the platform mock on your contest laptop, webcam on. Re-read your notes on I/O pitfalls and edge cases. The day before Round 1, one easy problem and sleep.
Round-day strategy
- Read all three statements in the first 10 minutes. Statements are long — extract input format, output format and constraints first.
- Solve the easy problem fully in the first 30–40 minutes; test N = 1 and all-equal inputs before submitting.
- Spend the next 60–75 minutes on the medium problem to a full solve.
- For the hard problem, submit the brute force that passes small cases first — partial marks are real marks — then optimise with what time remains.
- Never leave a problem with zero submissions; never tab out of the proctored window.
Prepare the PPI in parallel
From week 6, spend two hours a week on interview fundamentals: SQL with GROUP BY and window functions, OOP pillars and SOLID, process vs thread and deadlocks, HashMap internals, one design basic (rate limiter, load balancer). Keep a one-page note on each project on your résumé. The interview questions page is the checklist.
If you are also sitting the regular Infosys test, do HackWithInfy first: it covers the pseudocode section completely, and leaves aptitude and verbal for the final fortnight.