Engineering Blog 馃捇

Welcome to my software engineering blog! I’m currently studying leetcode (algorithms & data structures) and system design. As I go through this process, I will be publishing my study notes. Please reach out on Twitter or LinkedIn if you found something helpful, discovered a mistake, or if you would like to chat!

Leetcode 408: Valid Word Abbreviation

Problem Statement Description A string can be abbreviated by replacing any number of non-adjacent, non-empty substrings with their lengths. The lengths should not have leading zeros. For example, a string such as "substitution" could be abbreviated as (but not limited to): "s10n" ("s ubstitutio n") "sub4u4" ("sub stit u tion") "12" ("substitution") "su3i1u2on" ("su bst i t u ti on") "substitution" (no substrings replaced) The following are not valid abbreviations:...

August 23, 2023 路 3 min 路 512 words 路 Me

Leetcode 3: Longest Substring Without Repeating Characters

Problem Statement Description Given a string s, find the length of the longest substring without repeating characters. Examples Example 1: Input: s = "abcabcbb" Output: 3 Explanation: The answer is "abc", with the length of 3. Example 2: Input: s = "bbbbb" Output: 1 Explanation: The answer is "b", with the length of 1. Example 3: Input: s = "pwwkew" Output: 3 Explanation: The answer is "wke", with the length of 3....

April 16, 2023 路 3 min 路 434 words 路 Me

Leetcode 973: K Closest Points to Origin

Problem Statement Description Given an array of points where points[i] = [xi, yi] represents a point on the X-Y plane and an integer k, return the k closest points to the origin (0, 0). The distance between two points on the X-Y plane is the Euclidean distance (i.e., 鈭(x1 - x2)2 + (y1 - y2)2). You may return the answer in any order. The answer is guaranteed to be unique (except for the order that it is in)....

April 15, 2023 路 3 min 路 499 words 路 Me

Leetcode 238: Product of Array Except Self

Problem Statement Description Given an integer array nums, return an array answer such that answer[i] is equal to the product of all the elements of nums except nums[i]. The product of any prefix or suffix of nums is guaranteed to fit in a 32-bit integer. You must write an algorithm that runs in O(n) time and without using the division operation. Examples Example 1: Input: nums = [1,2,3,4] Output: [24,12,8,6] Example 2: Input: nums = [-1,1,0,-3,3] Output: [0,0,9,0,0] Constraints 2 <= nums....

February 20, 2023 路 3 min 路 509 words 路 Me

Leetcode 53: Maximum Subarray

Problem Statement Description Given an integer array nums, find the subarray with the largest sum, and return its sum. Examples Example 1: Input: nums = [-2,1,-3,4,-1,2,1,-5,4] Output: 6 Explanation: The subarray [4,-1,2,1] has the largest sum 6. Example 2: Input: nums = [1] Output: 1 Explanation: The subarray [1] has the largest sum 1. Example 3: Input: nums = [5,4,-1,7,8] Output: 23 Explanation: The subarray [5,4,-1,7,8] has the largest sum 23....

January 24, 2023 路 4 min 路 692 words 路 Me