Hello:)

Now I'll say what is Sparse Table and I'll show you some problems that I found.

Sparse Table is a data structure, that allows answering range queries. It can answer range minimum queries (or equivalent range maximum queries) in O(1) time, and another queries in O(log n).

You can read how to use it here: GeeksForGeeks, CP-Algorithms

Problems:

Codeforces:

872B - Maximum of Maximums of Minimums //difficulty 1200 but with sparse table harder

5C - Longest Regular Bracket Sequence //difficulty 1900

475D - CGCDSSQ //difficulty 2000

863E - Turn Off The TV //difficulty 2000

514D - R2D2 and Droid Army //difficulty 2100

675E - Trains and Statistic //difficulty 2500

15D - Map //difficulty 2500

873E - Awards For Contestants //difficulty 2500

713D - Animals and Puzzle //difficulty 2700

SPOJ:

SPOJ — RMQSQ //easy

SPOJ — THRBL

SPOJ — Miraculous

SPOJ — Postering

SPOJ — Negative Score

SPOJ — A Famous City

SPOJ — Diferencija

Everything you can solve by sparse table.