Most interview prep advice assumes you have 3-6 months and unlimited free evenings. Most people don't. Maybe you got a call for an interview loop in three weeks. Maybe you're job hunting on top of a full-time job. Maybe you just don't want to spend half a year grinding LeetCode before you feel "ready."
Here's a realistic 30-day plan that assumes 1-2 hours a day, and focuses on the things that actually move the needle in an interview — not just problem count.
The plan only works if you stop doing this first
Before the schedule: the single biggest time-waster in interview prep is solving random problems in random order with no plan for why you got one wrong. If a problem stumps you and you just look at the solution, read it, and move on — you'll forget it in a week. You have to know which pattern you missed, not just which problem you missed.
That's the whole plan, really: organize your practice by pattern, not by problem number.
Week 1 — Foundations + the 4 highest-frequency patterns
Spend day 1 reviewing time/space complexity and the patterns you'll drill: two pointers, sliding window, hashmaps, and binary search. These four alone cover a disproportionate share of "easy" and "medium" interview questions.
Days 2-4: two pointers + sliding window (aim for 3-4 problems per pattern, timed)
Days 5-6: hashmaps for frequency/lookup problems
Day 7: binary search, including the "search on the answer" variant that trips people up
By end of week 1, you should be able to name the pattern in a new problem within 2-3 minutes, even if you can't solve it yet.
Week 2 — Trees, graphs, and recursion
This is where most people's pace collapses, because trees and graphs have more variations than arrays. Don't try to memorize every traversal — understand the three or four templates (DFS, BFS, backtracking, and topological sort) deeply enough to adapt them.
Days 8-10: tree traversals + BST properties
Days 11-13: graph BFS/DFS, including grid-based problems (very common)
Day 14: recursion + backtracking basics (permutations, subsets)
Week 3 — Dynamic programming + a system design primer
DP is the pattern people fear most, and it's also the one where "practice by pattern" pays off the most, because most DP problems reduce to a handful of shapes (0/1 knapsack, unbounded knapsack, longest common subsequence, and interval DP).
Days 15-18: DP — 1D problems first (climbing stairs, house robber), then 2D
Days 19-20: if your target role includes system design, start now — don't leave it for the last week. Learn the vocabulary (load balancers, caching, sharding, CAP theorem) even before you can design a full system end to end
Day 21: rest or catch-up day — use it, don't skip it
Week 4 — Mock interviews and weak-spot triage
This is the week most self-taught plans skip entirely, and it's the highest-leverage week you have.
Days 22-25: timed mock interviews (with a friend, mentor, or a structured tool) — explaining your thinking out loud is a completely different skill from solving quietly, and you only build it by doing it
Days 26-28: revisit your weak pattern, not a random new one. If sliding window kept tripping you up in week 1, redo it now with fresh eyes.
Days 29-30: light review only. Sleep matters more than one more problem at this stage.
What actually separates a "pass" from a "borderline pass"
Having reviewed a lot of prep timelines, the difference usually isn't raw problem count. It's:
Talking through your approach before coding — interviewers are grading reasoning, not typing speed
Knowing your weak pattern and deliberately drilling it, instead of doing more of what you're already good at
Getting real timed practice under mild pressure before the actual interview, so the format isn't a surprise
If you want a structured way to follow this — organized by pattern instead of random problem lists, plus mock interview practice and language-specific Q&A — I built [InterviewPitch ](https://interviewpitch.com/)around exactly this approach. It's free.
What's your weak pattern? Curious what trips people up most under time pressure — drop it in the comments.
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