Amazon

1 Graph Valid Tree Medium 2 Cheapest Flights Within K Stops Medium 3 Decode Ways Medium 4 Longest Common Subsequence Medium 5 Edit Distance Hard 6 Hand of Straights Medium 7 Meeting Rooms Easy 8 Plus One Easy 9 Reverse Bits Easy 10 Group Anagrams Medium 11 Two Sum II - Input Array Is Sorted Medium 12 Permutation in String Medium 13 Daily Temperatures Medium 14 Search in Rotated Sorted Array Medium 15 Copy List with Random Pointer Medium 16 Invert Binary Tree Easy 17 Binary Tree Level Order Traversal Medium 18 Serialize and Deserialize Binary Tree Hard 19 Kth Largest Element in an Array Medium 20 Subsets II Medium 21 Clone Graph Medium 22 Course Schedule II Medium 23 Network Delay Time Medium 24 House Robber II Medium 25 Longest Increasing Subsequence Medium 26 Interleaving String Medium 27 Jump Game Medium 28 Insert Interval Medium 29 Spiral Matrix Medium 30 Single Number Easy 31 Contains Duplicate Easy 32 Encode and Decode Strings Medium 33 Best Time to Buy and Sell Stock Easy 34 Min Stack Medium 35 Search a 2D Matrix Medium 36 Merge Two Sorted Lists Easy 37 LRU Cache Medium 38 Same Tree Easy 39 Kth Smallest Element in a BST Medium 40 Kth Largest Element in a Stream Easy