LeetCode 300 Longest Increasing Subsequence - Binary Search Walkthrough

Trace the $O(n \log n)$ LIS on $[10, 9, 2, 5, 3, 7, 101, 18]$ using the tails array. $tails = []$. Process $10$: $tails = [10]$. Process $9$: replace $10$ with $9$, $tails = [9]$.

Process $2$: replace $9$, $tails = [2]$. Process $5$: append, $tails = [2, 5]$. Process $3$: replace $5$, $tails = [2, 3]$. Process $7$: append, $tails = [2, 3, 7]$. Process $101$: append, $tails = [2, 3, 7, 101]$. Process $18$: replace $101$, $tails = [2, 3, 7, 18]$. Length: $4$.