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PRACTICE LIBRARY
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Choose a challenge, then solve it in the existing Code Lab workspace.
28 available problems
Available28
Languages2
Evaluation modes2
ProblemDifficultyTopicTime
1.Mask Email UsernameFunction · JavaScript / PythonMediumDeveloper Skills25 minSolve →2.Running TotalsFunction · JavaScript / PythonMediumArrays25 minSolve →3.Deduplicate Preserving OrderFunction · JavaScript / PythonMediumArrays25 minSolve →4.Pagination Chunk CountFunction · JavaScript / PythonMediumDeveloper Skills25 minSolve →5.Inventory TotalFunction · JavaScript / PythonEasyDeveloper Skills12 minSolve →6.Normalize UsernameFunction · JavaScript / PythonMediumDeveloper Skills25 minSolve →7.Clamp ValueFunction · JavaScript / PythonEasyDeveloper Skills12 minSolve →8.Alphanumeric PalindromeFunction · JavaScript / PythonMediumStrings25 minSolve →9.Word LengthsFunction · JavaScript / PythonEasyStrings12 minSolve →10.Count VowelsFunction · JavaScript / PythonEasyStrings12 minSolve →11.Sum Odd IndicesFunction · JavaScript / PythonEasyArrays12 minSolve →12.Rotate LeftFunction · JavaScript / PythonMediumArrays25 minSolve →13.Array RangeFunction · JavaScript / PythonEasyArrays12 minSolve →14.Count Even ValuesFunction · JavaScript / PythonEasyArrays12 minSolve →15.Absolute DifferenceFunction · JavaScript / PythonEasyBasics12 minSolve →16.Sum Two NumbersFunction · JavaScript / PythonEasyBasics5 minSolve →17.Count Positive ValuesFunction · JavaScript / PythonEasyArrays10 minSolve →18.Normalize Pagination ParametersFunction · JavaScript / PythonEasyDeveloper Skills15 minSolve →19.Classify HTTP Response CodesFunction · JavaScript / PythonEasyDeveloper Skills12 minSolve →20.Calculate Retry BackoffFunction · JavaScript / PythonMediumDeveloper Skills20 minSolve →21.Add Two Numbers (Linked Lists)Function · JavaScript / PythonMediumLinked Lists25 minSolve →22.Reverse Word OrderFunction · JavaScript / PythonEasyStrings15 minSolve →23.Unique Sorted ValuesFunction · JavaScript / PythonEasyArrays15 minSolve →24.Balanced BracketsFunction · JavaScript / PythonMediumStack25 minSolve →25.First Unique CharacterFunction · JavaScript / PythonMediumStrings20 minSolve →26.Pair Sum IndicesFunction · JavaScript / PythonMediumArrays25 minSolve →27.Run Length EncodingFunction · JavaScript / PythonMediumStrings20 minSolve →28.Maximum Window SumFunction · JavaScript / PythonMediumSliding Window30 minSolve →Original, testable challenges. Choose a learning track for guided progression. The Code Lab editor design is unchanged.