599. Minimum Index Sum of Two Lists

Hashtable easy level algorithm

136. Single Number using XOR
242. Valid Anagram One more mistake to remind me to work on easy level
350. Intersection of Two Arrays II
389. Find the Difference using XOR
409. Longest Palindrome 
447. Number of Boomerangs
463. Island Perimeter 
500. Keyboard Row do it myself
500. Keyboard Row use HashSet API IsSubsetOf
575. Distribute Candies Need to work on my reading skills
599. Minimum Index Sum of Two Lists
706. Design HashMap Use fix size of space determined by upper bound
720. Longest Word in Dictionary use hashset
720. Longest Word in Dictionary use Trie data structure
720. Longest Word in Dictionary use Trie data structure
720. Longest Word in Dictionary use Queue data structure
720. Longest Word in Dictionary use recursive function