Problems

Hard · Suffix Array

Very easy · Graphs

Very easy · Brute force

Easy · Math · Binary Search

Very hard · Geometry · Constructive Algorithms

Very easy · Brute force

Hard · Graphs

Medium · Graphs · Greedy algorithms

Easy · Strings

Very easy · Sorting

Easy · Prefix Sums

Medium · Segment Tree

Easy · Dynamic programming · Graphs · Binary Search

Hard · Geometry

Hard · Brute force · Implementation

Easy · Dynamic programming · String suffix structures

Hard · Geometry · Constructive Algorithms

Very hard · Graphs · Depth-first Search · Trees · Combinatorics

Hard · Graphs · Depth-first Search · Shortest paths · Dijkstra algorithm

Medium · Math · Binary Search · Sorting

Easy · Brute force · Strings

Very hard · Graphs · Depth-first Search · Combinatorics · Number theory · Dynamic programming

Very hard · Trees · Constructive Algorithms · Graphs · Depth-first Search

Easy · Brute force · Math · Number theory

Very hard · Data Structures · Greedy algorithms · Sorting