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.

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: 5 days ago

Binary Search on a Sorted Array

Somewhat Frequent

Efficiently searching for a value in a sorted array.
Updated: 5 days ago

Binary Search

Somewhat Frequent

Binary searching on arbitrary monotonic functions.
Updated: 5 days ago

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: 4 days ago

Greedy Algorithms with Sorting

Somewhat Frequent

Solving greedy problems by sorting the input.
Updated: 5 days ago

Priority Queues

Not Frequent

A data structure that supports insert, query max, and pop max.
Updated: 4 days ago

Graph Traversal

Very Frequent

Traversing a graph with depth first search and breadth first search.

Flood Fill

Somewhat Frequent

Finding connected components in a graph represented by a grid.

Introduction to Tree Algorithms

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Introducing a special type of graph: trees.

Introduction to Functional Graphs

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

Intro to Bitwise Operators

Somewhat Frequent

Six bitwise operators and the common ways they are used.

Additional Practice for USACO Silver

Final tips for Silver and additional practice problems.