machines = [3,7,1,11,8]
k = 2

# machines = [3,9,4,2,16]
# k = 3

# machines = [3,2,6,1]
# k = 3

def calculateCost(machines,k):
    n = len(machines)
    leftSum = [0] * n
    rightSum = [0] * n

    # calculate cumulative connection cost from leftside
    totalSum = 0
    for i in range(1,n):
        totalSum += abs(machines[i] - machines[i-1])
        leftSum[i] = totalSum

    # calculate cumulative connection cost from rightside
    totalSum = 0
    for i in range(n-2,-1,-1):
        totalSum += abs(machines[i+1] - machines[i])
        rightSum[i] = totalSum

    #print(leftSum)
    #print(rightSum)

    l = 0
    r = l + k - 1
    res = math.inf
    while(r+1<=n):
        if(l == 0):
            #window is begining,
            currentCost = rightSum[r+1]
        elif(r == (n-1)):
            #window is at end
            currentCost = leftSum[l-1]
        else:
            # calculate cost of edge after removing window
            edgeCost = abs(machines[l-1] - machines[r+1])
            currentCost = rightSum[r+1] + leftSum[l-1] + edgeCost
        #print(l,r,currentCost)
        res = min(res,currentCost)
        l += 1
        r += 1

    return res

print(calculateCost(machines,k))