How Many LeetCode Problems Should You Solve Before Interviews?

The honest answer is "it depends," but that's not useful, so here's the number people actually quote: somewhere between 150 and 300 problems. Then here's why that number is close to meaningless on its own.

Why the number is the wrong question

Two candidates can both solve 200 problems and walk into an interview in completely different shape. One drilled 200 unique patterns across every major category. The other re-solved slight variations of the same 30 array problems 200 times because that's what showed up first in the sorted-by-popularity list. Same number, very different readiness.

The count is a byproduct of the prep, not the goal of it. Optimizing for it directly is how you end up with a big number and a blind spot.

What to actually track instead

• Category coverage, not raw count. Arrays and strings, trees and graphs, dynamic programming, two pointers and sliding window, heaps, backtracking. If you've solved 150 problems and 100 of them are arrays, you don't have 150 problems of coverage.
• Whether you can solve it again a week later without hints. If you needed the editorial the first time and can reproduce the approach cold a week later, that's a pattern you've actually learned. If you can only solve it because you remember the specific problem, that's memorization, and it won't transfer to a variant you haven't seen.
• Time under pressure, not just correctness. A problem solved correctly in 45 untimed minutes and a problem solved in 20 minutes with a clock running are not the same rep. Interviews are the second one.

A rough shape, if you want one

For a solid baseline across the common categories: 15-20 problems per major pattern, easy and medium difficulty mostly, a handful of hard ones per category so you've seen what "hard" looks like. That lands you in the 150-200 range naturally, but as a side effect of covering the patterns, not because 150-200 is a target with its own significance.

The part most study plans skip

Almost every plan is built around solving alone against a static list, then checking the answer. That's fine for building the pattern recognition in the first place. It does nothing to build the part interviews actually test: producing a correct answer while someone is watching and the clock is visible.

Once you've got baseline coverage, the higher-value rep isn't problem 201 off a list. It's taking problems you already know how to solve and doing them again under real time pressure, ideally against another person, so the pattern recognition you built alone actually holds up when it counts.