Method
two pointers
Articles
DP
Technique
Convex hull trick
A minimum of lines instead of a search: 1776 catalogue tests split into sandbox runs, and a quadratic DP becomes linear.
O(n)
2 problems
SYS
Data structure
Inverted index and BM25
A dictionary “word → documents that contain it”: a query reads a few short lists instead of all the texts.
O(total length of the query words' lists); AND by galloping O(m·log(n/m))
2 problems
Problems
Often together
dynamic programming 1 optimization 1 scheduling 1 segment tree 1 contests 1 searching 1 ranking 1 compression 1 binary search 1 search engines 1 databases 1 in production 1