Top 10 LeetCode problems for coding interviews

Coding interview is a process of assessing the programming skills and problem-solving abilities of a candidate for a software engineering position. It usually involves solving one or more coding problems in a limited time and explaining the logic and design choices to the interviewer.

One of the best ways to prepare for coding interview is to practice classic problems on LeetCode. By practicing following classic problems, you can improve your coding skills, learn new algorithms and data structures, test your knowledge, and gain confidence for the real interview.

1. Two Sum (Easy): Given an array of integers, return indices of the two numbers such that they add up to a specific target.
2. Reverse Integer (Easy): Reverse digits of an integer.
3. Palindrome Number (Easy): Determine whether an integer is a palindrome.
4. Roman to Integer (Easy): Convert a Roman numeral to an integer.
5. Longest Substring Without Repeating Characters (Medium): Given a string, find the length of the longest substring without repeating characters.
6. Median of Two Sorted Arrays (Hard): Find the median of two sorted arrays.
7. Merge Two Sorted Lists (Easy): Merge two sorted linked lists and return it as a new sorted list.
8. Maximum Subarray (Easy): Find the contiguous subarray (containing at least one number) that has the largest sum and return its sum.
9. Valid Parentheses (Easy): Given a string containing just the characters (, ), {, }, [ and ], determine if the input string is valid.
10. Merge Intervals (Medium): Given a collection of intervals, merge any overlapping intervals.

You will learn to manipulate arrays, strings, and integers efficiently, handle edge cases, and use data structures like hash tables and stacks. These problems will also introduce you to more advanced concepts such as binary search, dynamic programming, and interval manipulation.

To excel in interviews, it’s important not only to solve these problems but also to understand the underlying algorithms and data structures used to solve them efficiently. Additionally, practicing other LeetCode problems and participating in mock interviews can help you prepare comprehensively for technical interviews.