Silver

Introduction to Prefix Sums

Somewhat Frequent

Computing range sum queries in constant time over a fixed 1D array.
Updated: 2 weeks ago

More on Prefix Sums

Not Frequent

Max subarray sum, prefix sums in two dimensions, and a more complicated example.
Updated: Last week

Custom Comparators and Coordinate Compression

Somewhat Frequent

Using a custom comparator to sort custom objects or values in a non-default order, and compressing values from a large range to a smaller one.
Updated: 2 weeks ago

Two Pointers

Not Frequent

Iterating two monotonic pointers across an array to search for a pair of indices satisfying some condition in linear time.

More Operations on Sorted Sets

Not Frequent

Finding the next element smaller or larger than a specified key in a set, and using iterators with sets.
Updated: 2 weeks ago

(Optional) C++ Sets with Custom Comparators

Rare

Incorporating custom comparators into standard library containers.

Greedy Algorithms with Sorting

Somewhat Frequent

Solving greedy problems by sorting the input.
Updated: 2 weeks ago

Binary Search

Somewhat Frequent

Binary searching on arbitrary monotonic functions and built-in functions for binary search.
Updated: 2 weeks ago

Graph Traversal

Very Frequent

Traversing a graph with depth first search and breadth first search.
Updated: 2 weeks ago

Flood Fill

Somewhat Frequent

Finding connected components in a graph represented by a grid.
Updated: 2 weeks ago

Introduction to Tree Algorithms

Not Frequent

Introducing a special type of graph: trees.
Updated: 2 weeks ago

Introduction to Functional Graphs

Not Frequent

Directed graphs in which every vertex has exactly one outgoing edge.
Updated: 2 weeks ago

Intro to Bitwise Operators

Somewhat Frequent

Six bitwise operators and the common ways they are used.
Updated: Last month

Additional Practice for USACO Silver

Final tips for Silver and additional practice problems.