Problems

Hard · Dynamic programming

Very easy · Dynamic programming · Combinatorics

Easy · Dynamic programming · Matrix

Medium · Dynamic programming

Medium · Dynamic programming · Graphs

Easy · Strings · Combinatorics

Easy · Matrix · Dynamic programming · Math · Dijkstra algorithm

Easy · Dynamic programming

Easy · Sorting

Medium · Z-function · Strings

Very easy · Graphs

Very hard · Graphs

Very easy · Graphs · Graph network flows

Very easy · Graph network flows · Shortest paths

Easy · Brute force

Very easy · Prefix Sums · Fenwick Tree

Hard · String suffix structures · Sorting

Hard · Meet-in-the-middle · Binary Search · Sorting · Greedy algorithms

Easy · Strings · Brute force

Very hard · Combinatorics

Medium · Brute force

Very easy · Math · Greedy algorithms

Very easy · Brute force

Easy · Geometry

Medium · Data Structures · Hashing