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1. What does this program print? ``

python
def reverse(a, left, right):
    while left < right:
        a[left], a[right] = a[right], a[left]
        left += 1
        right -= 1

def rotate_right(a, k):
    n = len(a)
    k = k % n
    reverse(a, 0, n - 1)
    reverse(a, 0, k - 1)
    reverse(a, k, n - 1)

a = [1, 2, 3, 4, 5]
rotate_right(a, 2)
print(a)

``

[3, 4, 5, 1, 2][4, 5, 1, 2, 3][2, 3, 4, 5, 1][5, 4, 3, 2, 1]

2. In the rotation by reversal method, the last k items move to the front. What word does the lesson use for those last k items? Type one word.

Type your answer.

3. What does this program print? ``

python
def add_range(diff, left, right, value):
    diff[left] += value
    diff[right + 1] -= value

def recover(diff, n):
    result = [0] * n
    running = 0
    for i in range(n):
        running += diff[i]
        result[i] = running
    return result

diff = [0] * 5
add_range(diff, 0, 2, 4)
add_range(diff, 2, 3, -1)
print(recover(diff, 4))

``

[4, 4, 4, 0][4, 0, -1, -4][4, 4, 3, -1][4, 4, 3, 0]

4. To add value to every position from left to right in a difference array, the code is diff[left] += value and diff[____] -= value. Type the index expression that goes in the blank.

Type your answer.

5. Why does the rotation method run k = k % n before it does any reversal?

It stops a step count larger than the length from sending a reversal range outside the listIt sorts the list so the reversals are simplerIt doubles the list length to make room for the rotationIt copies the list so the caller's copy is not changed

Rotation and differences