Educational & Professional · Computers & Internet

Cracking Leetcode 75

Learn the Trick, Not the Puzzle

by Lokesh Bhoyar

The 75 problems everyone grinds through are really about ten ideas wearing 75 different hats: sliding window, two pointers, prefix sums, monotonic stacks, binary search on the answer, dynamic programming.

Learn the ten, and the seventy-five stop being seventy-five separate things to memorise. The solutions are in pseudocode rather than any one language, so the thinking transfers to whatever you write in.

Pages: 374
Chapters: 22
Problems: 75
Formats: 4

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Five pages per problem

Every one of the 75 problems is laid out the same way, so you always know where you are and how much help the next page is about to give you.

The story
Where this shape of problem actually shows up, before any code appears.
The problem
Stated plainly, with the constraints that decide which pattern applies.
The thinking page
Space to work it out yourself. This is the page that does the teaching.
The hint
One nudge toward the right idea, worded to unstick you without giving the answer away.
The solution
Worked through in pseudocode, so you can see why each step is there.

The ten ideas

Twenty-two chapters build these up one at a time, and each chapter closes with a one-page revision summary you can come back to the night before an interview.