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Code Practice
Sudoku keeps most people's minds sharp, but for a developer it's too easy. So here are puzzles that compile, each one a puzzle and a piece of real work.
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0 of 12 solved
- 01Count by the fourth wordOnly the lines whose third word is error, in any case.EasyStringsParsing
- 01The second largest numberNot the largest, the one after it.EasyRankingSubqueries
- 02The k-th chunk of a listCut a list into equal chunks and return one of them.EasyBugsLists
- 02Add as you goEach step's total so far.EasyWindowsSums
- 03Merge two lists, each key onceKeys match in any case, spaces aside.MediumDataStrings
- 03Who got no letter?Names with nothing pointing at them.EasyJoinsNULL
- 04Split on commas, but not inside quotesAnd a quote inside quotes comes doubled.HardParsingStrings
- 04Each pile's shareWhat part of the whole, in percent?MediumWindowsMath
- 05The two tallest on each streetPer street, its two tallest houses.MediumRankingWindows
- 05Two numbers that add upWhich two in the list make the target?EasyArraysHashing
- 06Balanced bracketsIs every ( [ { closed, in the right order?EasyStacksStrings
- 06Keep the first of eachWhich rows repeat a code seen before?MediumWindowsStrings
- 07The longest run with no repeatsThe longest stretch of a list with no value twice.MediumArraysSliding window
- 07Runs of numbersWhere does each unbroken run start and end?HardGaps and islandsWindows
- 08How deep is each node?Count the steps up to the root.HardRecursionTrees
- 08Shortest way out of the mazeFrom the top left to the bottom right, fewest steps.HardGraphsSearch
- 09FizzBuzz, for old times' sakeThe whiteboard classic. Yes, that one.EasyLoops
- 10Does it read the same backwards?Letters and digits only, any case.EasyStringsTwo pointers
- 11Ways up the stairsOne step or two at a time. How many ways?MediumDynamic programming
- 12Place the queensn queens on an n × n board, none attacking another.HardBacktracking
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