Coding interview practice

Practice that remembers what you miss

exgrind is spaced repetition for programming problems. Track your progress automatically, and the concepts you are shaky on come back until they stick.

Try it out See how it works

Two Sum

1  def solve(nums, target):
2    seen = {}
3    visited = []
4    for i, n in enumerate(nums):
5      ...

Tests40/40O(time)O(n)O(space)O(n)Style2/2

CoachingRight overall approach, but extra memory. visited repeats what seen ...

Comes backhash-map in 6 problems

Solving it once isn't the end

Practice makes concepts stick, but undirected prep is an inefficient grind. Skip that - exgrind helps you review using smart, spaced repetition.

with exgrindsolved once30 problems

Practice made perfect

Spaced repetition

Concepts return before they fade

Each problem is tagged with the concepts it tests. When a concept slips, exgrind queues a fresh problem to reinforce it. When it starts to stick, the gap before the next one grows.

two-pointersnext review in 12 problems

#1#4#6#13#30

A missed concept comes back two problems later, not twenty.

Intelligent grading

Graded like an interviewer

Comprehensive test suites check your code. Then, a smart reviewer reads your code like an interviewer: covering time & space complexity, readability, and constructive feedback.

All 51 hidden tests passed

O(n^2)The inner loop rescans the window each step. Track the last index of each character and the window only moves forward: O(n).