Silver

Introduction to Prefix Sums

Somewhat Frequent

Computing range sum queries in constant time over a fixed 1D array.
Updated: Last month

More on Prefix Sums

Not Frequent

Max subarray sum, prefix sums in two dimensions, and a more complicated example.

Custom Comparators and Coordinate Compression

Somewhat Frequent

Using a custom comparator to sort custom objects or values in a non-default order; Coordinate compressing values from a large range to a smaller one.

Two Pointers

Not Frequent

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

More Operations on Sorted Sets

Not Frequent

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

(Optional) C++ Sets with Custom Comparators

Rare

Incorporating custom comparators into standard library containers.
Updated: 2 weeks ago

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: Last week

Depth First Search (DFS)

Very Frequent

Recursively traversing a graph.
Updated: 3 weeks ago

Flood Fill

Somewhat Frequent

Finding connected components in a graph represented by a grid.
Updated: 3 weeks ago

Introduction to Tree Algorithms

Rare

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

(Optional) Introduction to Functional Graphs

Rare

Directed graphs in which every vertex has exactly one outgoing edge.

Additional Practice for USACO Silver

Congratulations on making it this far! Here are some final tips for Silver, as well as additional practice problems you may find useful.