Given aContinue reading “[Leetcode]421. Maximum XOR of Two Numbers in an Array”non-emptyarray of numbers, a_{0}, a_{1}, a_{2}, … , a_{n-1}, where 0 ≤ a_{i}< 2^{31}. Find the maximum result of a_{i}XOR a_{j}, where 0 ≤i,j<n. Could you do this in O(n) runtime?

## [Leetcode]212. Word Search II

Given a 2D board and a list of words from the dictionary, find all words in the board. Each word must be constructed from letters of sequentially adjacent cell, where "adjacent" cells are those horizontally or vertically neighboring. The same letter cell may not be used more than once in a word.Continue reading “[Leetcode]212. Word Search II”Example:Input:board= [ ['o','a','a','n'], ['e','t','a','e'], ['i','h','k','r'], ['i','f','l','v'] ]words=`["oath","pea","eat","rain"]`

Output:`["eat","oath"]`

## Intro to Trie (Prefix Tree) – FEAT. Leetcode 208. Implement Trie

A trie, or a prefix tree, refers to an ordered data structure that is usually used to store strings (Wikipedia). The picture on the above is an example where a trie stores `[ape,apple,are,art]`

. Now let’s take a closer look at it and it’s not hard to find that: