Julia AOC 2020 Day 9 Part 2

function part2(invalid, arr::Vector{Int64})
    n = length(arr)
    low,high = n-1,n
    runsum = arr[low] + arr[high]
    while runsum != invalid
        if runsum < invalid
            low -= 1
            runsum += arr[low]
        else
            runsum -= arr[high]
            high -= 1
        end
    end
    sum(extrema(@view arr[low:high]))
end