Kotlin Programming: The Big Nerd Ranch Guide, First Edition

Challenge: Sliding Window

For this advanced challenge, begin with this list of values:

    val valuesToAdd = listOf(1, 18, 73, 3, 44, 6, 1, 33, 2, 22, 5, 7)

Using a functional programming approach, perform the following operations on the valuesToAdd list:

1. Exclude any number less than 5.

2. Group the numbers in pairs.

3. Multiply the two numbers in each pair.

4. Sum the resulting products to produce a final number.

The correct result is 2,339. Walking through each step, here is what the data should look like along the way:

    Step 1: 1, 18, 73, 3, 44, 6, 1, 33, 2, 22, 5, 7
    Step 2: 18, 73, 44, 6, 33, 22, 5, 7
    Step 3: [18*73], [44*6], [33*22], [5*7]
    Step 4: 1314 + 264 + 726 + 35 = 2339

Notice that step 3 groups the list into sublists ...