Problems

Medium · Graphs

Easy · Segment Tree · Binary Search

Very hard · Sorting

Hard · Math · Number theory · Disjoint set union · Graphs

Hard · Number theory · Combinatorics

Hard · Breadth-first Search · Graphs · Implementation

Very easy · Implementation

Very easy · Dynamic programming · Math

Very easy · Graphs

Very hard · Graphs

Hard · Math · Constructive Algorithms · Greedy algorithms

Very hard · Dynamic programming · Segment Tree · Divide and Conquer · Math

Hard · Queries · Prefix Sums

Very hard · Dynamic programming · Math

Hard · Games · Combinatorics · Greedy algorithms

Very hard · Suffix Array · Strings

Very hard · Strings · Data Structures

Very hard · Suffix Array · Strings

Very easy · Suffix Array · Binary Search

Medium · Dynamic programming · String suffix structures

Very easy · Geometry

Hard · Geometry · String suffix structures

Hard · Games · Graphs · Combinatorics

Medium · Dynamic programming · Bitmasks

Very easy · Number theory · Math