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##  #   ##      ##      ## ##    # #    #    # #   ##
##   #  ######  ##       ###      #    ###    #    ######

$ curl repovive.com/roadmaps/math-fundamentals/sets/consecutive-implementation

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#####   ######  #####    ###    #   #  ###  #   #  ######
##  ##  ##      ##  ##  ## ##   #   #   #   #   #  ##
#####   ####    #####   #   #   #   #   #   #   #  ####
##  #   ##      ##      ## ##    # #    #    # #   ##
##   #  ######  ##       ###      #    ###    #    ######

$ curl repovive.com/roadmaps/math-fundamentals/sets/consecutive-implementation

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Consecutive - Implementation - Sets | Math Fundamentals | Repovive

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Math Fundamentals18 sections · 842 units13h total

Open in Course

Consecutive - Implementation

Smart iteration

Here is the solution:


function longestConsecutive(nums)
    numSet := convert nums to set
    maxLength := 0
    for each num in numSet
        if (num - 1) not in numSet then
            currentNum := num
            currentLength := 1
            while (currentNum + 1) in numSet
                currentNum := currentNum + 1
                currentLength := currentLength + 1
            maxLength := max(maxLength, currentLength)
    return maxLength

You only start counting from numbers that are sequence starts. Time: $O(n)$ , Space: $O(n)$ .