Problems

Very easy · Graphs

Easy · Greedy algorithms · Sorting

Hard · Math · Constructive Algorithms

Medium · Trees · Greedy algorithms · Sorting

Very easy · Brute force · Strings

Medium · Math · Greedy algorithms

Medium · Graph matchings · Greedy algorithms

Very easy · Combinatorics · Dynamic programming

Medium · Prefix Sums

Medium · Graphs · Games · Dynamic programming

Very hard · Geometry

Easy · Dynamic programming · Greedy algorithms

Easy · Implementation · Strings

Very hard · Number theory · Prime factorization · Math

Medium · Brute force · Math

Easy · Dynamic programming

Hard · Math · Combinatorics

Very hard · Shortest paths · Breadth-first Search · Dijkstra algorithm · Graphs · Dynamic programming

Medium · Disjoint set union

Very hard · Geometry

Hard · Binary Search · Graphs · Depth-first Search · Constructive Algorithms

Hard · Binary Search · Dynamic programming

Easy · Geometry · Implementation

Easy · Dynamic programming · Matrix

Hard · Dynamic programming