My Journey of Repeating LeetCode: Turning Obstacles into Interview Success

Preface

Recently I have been organizing the algorithm problems I solved on Leetcode. I compiled them into a small booklet that contains more than 150 high‑frequency questions (about 80,000 words and over 120 illustrations). The algorithm language used is Go. The repository is available at https://github.com/gofish2020/algorithm-go and the original questions come from https://codetop.cc/home.

I wrote this to share my experience because I used to be very resistant to algorithms. Now I am no longer afraid of them; inventing a new algorithm would be a challenge, but practicing existing ones helps train thinking and provides inspiration when solving real problems or reading open‑source projects.

For example, the Gin source code contains a "compressed prefix tree" algorithm, an improvement over the classic prefix tree. Knowing that it is used for string matching instantly puts you ahead of many interviewees. The basic prefix tree is simple yet widely applicable to any string‑matching or search task, and I consider it a fundamental piece of interview knowledge.

Insights

The core of learning new knowledge is repetition + repetition + repetition . I started from zero, struggled, and gradually improved. After the first round of solving problems I was confused, but by the fifth round I could recall the general solution direction from the title alone. By the eighth round the patterns became familiar.

Solving problems (essentially memorizing solutions) is aimed at interview preparation, so it is better to select a high‑hit‑rate problem set rather than starting from the very first LeetCode question. After memorizing about 300 problems, I felt excited during interviews because the questions matched what I had practiced.

Do not imagine algorithm questions as lofty; they have answers and solving patterns. Memorize the answers and summarize the patterns; even if a new problem looks confusing, you can often infer a solution by analogy.

All the problems I used come from https://codetop.cc/home, which marks high‑frequency questions based on interview hit rates. The purpose of this article is to provide reference solutions with line‑by‑line explanations and common patterns, making it easier to understand and memorize.

When using the website, simply mark whether you have attempted a problem (the note‑taking feature is paid). Keep your own solutions on the official LeetCode platform.

Suggestion: after solving each problem, write down your thoughts in your own solution notes to facilitate review and memorization.

I have solved roughly 300+ problems. When you read a problem, try to think of a solution, then look at the answer, hand‑write the code, and record your understanding. One pass is never enough; repeatedly review accumulated problems to solidify knowledge.

For beginners, a helpful algorithm book is available at https://www.hello-algo.com/, which is popular on GitHub and can be used to fill gaps or clarify difficulties encountered while practicing.

Finally, to fellow CodeTop algorithm enthusiasts: "Learn one more minute, turn obstacles into opportunities, and turn problems into possibilities." Sincerely.