Problems

Practice coding problems

Build problem-solving habits with topic filters, difficulty levels, visible examples, and an online code workspace.

Follow a guided ladder

Choose a Python Foundations, coding practice, or PCEP review path and work through problems in order.

View ladders

Difficulty

AllBeginnerIntermediateHard

Topic

All topicsArraysConditionalsDictionariesDynamic ProgrammingFunctionsGraphsGreedyHashmapInput/OutputListsLoopsPrefix SumsSimulationSortingStringsVariables

Showing 1 of 30 problems

Clear filters
BeginnerHashmap

Two Summer

Given a number n and a list A of size n provide the count of all pairs that add up to every number in list B of size n.

Open problem