My Transition to Coding: How to Learn the Basics of Java Algorithms?

Learning the basics of Java algorithms for me is like playing a high-score game, and the deeper you go, the more you feel a sense of accomplishment. At first, I thought Java was about writing simple code and solving small problems, but gradually I found that to really master Java, especially algorithms, it takes a little effort. The algorithm part, especially for those who want to do SDE, is simply an inescapable difficulty.

Basics of Language Learning

Just started to learn the algorithm. I think the most important thing is to lay a good language foundation. For example, you must first familiarize yourself with the basic syntax of Java algorithms, figure out what functions commonly used libraries have, such as data structures, arrays, linked lists, stacks, queues, hash tables, trees, and these basic structures must be understood. Then there's the Set framework, the List, the set, the Map containers that you have to know how to use, and you have to understand their time complexity, and the efficiency of the algorithm is often directly related to these. And recursion, understanding how recursion works, figuring out how to draw a recursion tree, being able to analyze the time complexity of recursion, those are the foundational parts.

Start with a Simple Question

After that, I started with simple sorting algorithms, such as bubble sort, quick sort, merge sort, and I repeatedly did these problems to figure out their time complexity, the advantages and disadvantages of each sorting algorithm, and the applicable scenarios.

Grind Questions

Then, I started to brush questions, LeetCode, HackerRank, Codeforces became my essential tools. I remember at first doing simple two-pointer problems, like Two Sum, many times before I started to understand the rules. Later, I gradually challenged myself to do more difficult ones, such as the largest subarray of sliding Windows and problems, and Fibonacci sequences for dynamic programming.

Understand the Nature of the Algorithm

And every time I do a problem, I'll summarize it and say. Why did I choose this algorithm? If the time complexity of the algorithm is high, can I optimize it? How can I go from O(n^2) to O(n)? Through these exercises, I slowly found that solving problems is not only about memorizing the code, but more about understanding the logic behind the algorithm.

Every time I go back to the old problem and find that I have done it quickly and well, the sense of accomplishment is really indescribable. I began to summarize my own ideas for solving the problem, such as the application scenarios of DFS and BFS, how to write the state transition equation of dynamic programming, and what are the common tips for optimizing the algorithm. In the process of learning the basics of Java algorithms, there is no shortcut to go, and every time you break through yourself, it is a kind of progress.