Question: How many envelops can you fit into another? Each envelope has a 2D representation. [4,5] -> width = 4, length = 5 How many envelops can you fit into one another without rotating any envelopes. Bare in mind you can’t fit in two evelopes with same width or height. This is question is very much like a Russian Doll question. Which that question itself uses an Longest increasing subsequence algorithm to solve....
Attention: This post was updated to include the alternate solution that uses binary search. It reduces the Time Complexity from O(n * n) to O(n * log n). Before we present the question. Let’s figure out what a subsequence is: What’s a subsequence? Any selection of items from the original array. The selection must respect the order. Meaning for [1,2,3,4,5] only two of the four below are subsequences: [1,2,3,4,5] ✅ [1,4,3,2,5] ❌ order not respected [1,2,5] ✅ [5,1] ❌ order not respected What’s the difference between a subsequence and a subarray?...