Problems

Easy · Scanline / Sweep Line · Sorting · Data Structures · Geometry

Medium · Dijkstra algorithm · Shortest paths · Graphs

Very easy · Dynamic programming · Graphs · Shortest paths

Hard · Sorting · Geometry

Hard · Dynamic programming · Bitmasks · Binary Search

Very hard · Depth-first Search · Dynamic programming · Graphs · Shortest paths

Easy · Greedy algorithms · Strings

Medium · Greedy algorithms · Math

Hard · Combinatorics · Sorting · Greedy algorithms

Hard · Graphs · Depth-first Search · Disjoint set union · Implementation

Hard · Greedy algorithms · Stacks · Prefix Sums · Queries

Hard · Constructive Algorithms · Greedy algorithms · Prefix Sums

Very easy · Bitmasks · Dynamic programming · Combinatorics

Hard · Shortest paths · Breadth-first Search · Graphs

Very hard · Graphs · Sorting · Two pointers · Data Structures

Hard · Breadth-first Search · Graphs · Combinatorics · Prefix Sums · Number theory

Very hard · Dynamic programming · Dynamic Programming Optimization · Binary Search · Stacks

Very hard · Graphs · Depth-first Search · Fenwick Tree · Prefix Sums · Data Structures

Medium · Implementation

Easy · Implementation

Very easy · Math · Geometry

Hard · Breadth-first Search · Greedy algorithms

Medium · Greedy algorithms · Sorting

Very hard · Dynamic programming · Prefix Sums · Data Structures

Hard · Games · Combinatorics · Prefix Sums · Number theory · Greedy algorithms