Problems

Hard · Greedy algorithms · Sorting · Combinatorics · Number theory · Implementation

Medium · Greedy algorithms · Sorting · Data Structures

Very hard · Dynamic programming · Greedy algorithms · Sorting · Combinatorics

Medium · Graphs · Disjoint set union

Medium · Dynamic programming

Very easy · Implementation · Prefix Sums

Easy · Geometry

Easy · Math · Brute force

Easy · Games

Medium · Dynamic programming · String suffix structures

Hard · Segment Tree · Math

Medium · Brute force · Combinatorics

Medium · Dijkstra algorithm · Shortest paths · Graphs

Easy · Math · Fast Fourier transform · Dynamic programming · Implementation

Easy · Graphs

Hard · Breadth-first Search · Graphs · Hashing

Hard · Depth-first Search · Sorting · Scanline / Sweep Line · Data Structures · Two pointers

Hard · Geometry · Sorting

Easy · Sorting · Geometry

Very easy · Math

Easy · Graphs · Implementation

Very easy · Math

Very easy · Math

Very easy · Graphs

Very hard · String suffix structures