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$ curl repovive.com/roadmaps/math-fundamentals/sequences-summations/arithmetic-slices-implementation

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$ curl repovive.com/roadmaps/math-fundamentals/sequences-summations/arithmetic-slices-implementation

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Arithmetic Slices - Implementation - Sequences & Summations | Math Fundamentals | Repovive

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Math Fundamentals18 sections · 842 units13h total

Open in Course

Arithmetic Slices - Implementation

In pseudocode

Here's the solution:


function numberOfArithmeticSlices(nums)
    n := length of nums
    if n < 3 then
        return 0
    count := 0
    length := 2  // current arithmetic sequence length
    for i from 2 to n - 1
        if nums[i] - nums[i - 1] = nums[i - 1] - nums[i - 2] then
            length := length + 1
        else
            if length ≥ 3 then
                k := length - 2
                count := count + (k × (k + 1)) / 2
            length := 2
    if length ≥ 3 then
        k := length - 2
        count := count + (k × (k + 1)) / 2
    return count

The formula $(k \times (k + 1)) / 2$ counts slices for a sequence of length $length = k + 2$ . This runs in $O(n)$ time.