Ikwhan Chang
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Category: Tech

[LC] 42. Trapping Rain Water

Given n non-negative integers representing an elevation map where the width of each bar is 1, compute how much water it can trap after raining. Example 1: Input: height = [0,1,0,2,1,0,1,3,2,1,2,1] Output: 6 Explanation: The above elevation map (black section) is represented by array [0,1,0,2,1,0,1,3,2,1,2,1]. In this case, 6 units of rain water (blue section) are being trapped. ...

[LC] 200. Number of Islands

Given an m x n 2d grid map of '1's (land) and '0's (water), return the number of islands. An island is surrounded by water and is formed by connecting adjacent lands horizontally or vertically. You may assume all four edges of the grid are all surrounded by water. Approach Simple breath first search (BFS). Nothing special. Just keep looking for non visited grid ...

[LC] 146. LRU Cache

Design a data structure that follows the constraints of a Least Recently Used (LRU) cache. Implement the LRUCache class: LRUCache(int capacity) Initialize the LRU cache with positive size capacity. int get(int key) Return the value of the key if the key exists, otherwise return -1. void put(int key, int value) Update the value of the key if the key exists. Otherwise, add the key-value pair to the cache. If the number of keys ...

[LC] 91. Decode Ways

A message containing letters from A-Z can be encoded into numbers using the following mapping: 'A' -> "1" 'B' -> "2" ... 'Z' -> "26" To decode an encoded message, all the digits must be mapped back into letters using the reverse of the mapping above (there may be multiple ways). For example, "111" can have each of its "1"s be mapped into 'A's to ...

[LC] 1. Two Sum

https://leetcode.com/problems/two-sum/ Question Given an array of integers nums and an integer target, return indices of the two numbers such that they add up to target. You may assume that each input would have exactly one solution, and you may not use the same element twice. You can return the answer in any order. Thoughts There is probably a bunch of solution since it is ...

Fast development or future-oriented development?

When I think about development, I feel that the most important part is whether I can get the maximum possible operation with minimal resources and prepare for large scale. That’s why I chose the micro service architecture, and if you automatically scale the resources used by the Docker to match the global, you will not worry about ...