For developers

Skill-Based Coding Practice

1167+ problems to build durable fundamentals. Filter by role, topic, and difficulty, then jump straight to the next challenge.

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Role filters are skill maps

These tracks organize public practice by transferable skills. They are not employer question lists or claims about any private interview process.

Role track

Every auto-gradable coding, SQL, data, and ML problem.

Showing 1-50 of 1167 matching problems (1167 total)

Accuracy Score

EasyMachine Learning

Actors and Directors

EasySQL

Add Binary

EasyString

Add Digits

EasyMathTree

Add Strings

EasyString

Add to Array-Form of Integer

EasyArrayMath+1

Ads Performance

EasySortingSQL

Array Maximum

EasyArray

Array Minimum

EasyArray

Array Pair Sum

EasyArrayGreedy+1

Array Partition

EasyArray

Article Views I

EasySortingSQL

Assign Cookies

EasyGreedySorting

Average of Levels in Binary Tree

EasyArrayBFS+4

Average Salary By Department

EasySortingSQL

Backspace String Compare

EasyString

Backward-Fill Nulls

EasyArrayData Engineering

Balanced Binary Tree

EasyBinary TreeGraph+3

Base 7

EasyString

Baseball Game

EasySimulation

Best Time to Buy and Sell Stock

EasyArrayGreedy

Big Countries

EasySQL

Biggest Single Number

EasyMathSQL

Binarize

EasyArrayMachine Learning

Binary Gap

EasyBit Manipulation

Binary Search

EasyArrayBinary Search+1

Binary Tree Paths

EasyBinary TreeGraph+3

Binary Watch

EasyBit ManipulationMath

Calculate Digit Sum of a String

EasyMathString

Calculate Special Bonus

EasySQL

Can Make Arithmetic Progression

EasyArraySorting

Can Make Arithmetic Progression From Sequence

EasyArraySorting

Can Place Flowers

EasyArrayGreedy

Capitalize the Title

EasyString

Capitalize Words

EasyString

Cells with Odd Values

EasyMathMatrix

Chebyshev Distance

EasyMachine LearningMath

Check if Array Is Sorted and Rotated

EasyArrayBinary Search+2

Check If N and Its Double Exist

EasyArray

Check if the Sentence Is Pangram

EasySortingString

Check If Two String Arrays are Equivalent

EasyArrayString

Chunk Array

EasyArrayData Engineering

Classes More Than 5 Students

EasyMathSQL

Climbing Stairs

EasyDynamic ProgrammingMath+1

Clip Values

EasyArrayMachine Learning

Coalesce Columns

EasyArrayData Engineering

Combinations (n choose k)

EasyMathProbability

Combine Two Tables

EasySQL

Complement of Base 10 Integer

EasyBit Manipulation

Consecutive Differences

EasyArrayData Engineering
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