Practice · judged on hidden tests
Problems
100 problems, ordered so each topic builds on the last.
- Not startedMerging many sorted lists at onceSorting, Heaps, ArraysHard
- Not startedMirror the treeTreesEasy
- Not startedMost frequent numbersSorting, Heaps, ArraysMedium
- Not startedMove the zeroes to the endArrays, Two pointersEasy
- Not startedProduct of everything elseArrays, Prefix sumsMedium
- Not startedRaising to a power without multiplying that many timesBasics, NumbersMedium
- Not startedReading a tree one level at a timeTrees, Stacks and queuesMedium
- Not startedReads the same backwardsBasics, NumbersEasy
- Not startedRead the grid in a spiralArrays, MatricesMedium
- Not startedRunning sumArrays, Prefix sumsEasy
- Not startedSearch insert positionArrays, Binary searchEasy
- Not startedSharing the books so nobody reads too muchArrays, Binary searchMedium
- Not startedShortest stretch that reaches the targetSliding window, ArraysMedium
- Not startedSorting 0s, 1s and 2s in one passSorting, Arrays, Two pointersMedium
- Not startedSqueeze out the duplicatesArrays, Two pointersEasy
- Not startedThe best k days in a rowSliding window, ArraysEasy
- Not startedThe best you can take without touching neighboursDynamic programming, ArraysMedium
- Not startedThe biggest rectangle inside a histogramStacks and queues, ArraysHard
- Not startedThe cheapest way down through the gridDynamic programming, Arrays, MatricesMedium
- Not startedThe deepest node both of them are underTreesMedium
- Not startedThe first letter that has appeared only once, so farStrings, Stacks and queues, Hash mapsMedium
- Not startedThe first negative number in every windowSliding window, Stacks and queues, ArraysMedium
- Not startedThe kth largest, without sorting everythingHeaps, ArraysMedium
- Not startedThe kth smallest value in a search treeTrees, Binary searchMedium
- Not startedThe largest number in every windowSliding window, Stacks and queues, ArraysHard