Problems

Very easy · Number theory

Very easy · Math

Easy · Brute force

Very easy · Implementation

Very easy · Dynamic programming

Hard · Geometry

Easy · String suffix structures · Math

Very easy · Hashing

Easy · Implementation

Medium · Shortest paths · Graphs

Hard · Graphs · Depth-first Search

Medium · Graphs · Brute force · Depth-first Search

Hard · Graphs · Depth-first Search · Breadth-first Search

Medium

Medium · Dynamic programming · Breadth-first Search · Shortest paths

Very hard · Graphs · Dynamic programming

Very easy · Geometry

Hard · Greedy algorithms · Sorting · Scanline / Sweep Line

Easy · Geometry

Medium · Dynamic programming · Prefix Sums

Easy · Brute force · Dynamic programming

Easy · Implementation

Medium · Number theory · Math

Easy · Number theory · Math

Easy · Brute force · Math