Cracking Leetcode 75

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 you are about to be given.

1. The story

   Where this shape of problem actually shows up, before any code appears.

2. The problem

   Stated plainly, with the constraints that decide which pattern applies.

3. The thinking page

   Space to work it out yourself. This is the page that does the teaching.

4. The hint

   One nudge toward the right idea — enough to unstick you, not enough to spoil it.

5. The solution

   Worked through in pseudocode, with the reasoning kept in view.

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.

• Sliding windowA range that moves, not restarts
• Two pointersClose in from both ends
• Prefix sumsPay once, answer any range
• Monotonic stacksKeep only what can still win
• Binary search on the answerGuess, check, halve
• Dynamic programmingSolve once, reuse forever
• HashingTrade memory for lookups
• Graphs & traversalFollow the edges outward
• HeapsThe best item, always on top
• BacktrackingTry a branch, undo, try the next

Where to buy

Available now in ebook, paperback and hardcover. More stores are on the way.