Recursion: Left Shift By Powers of Two

The left shift operation is similar to multiplication by powers of two, thus, the process is repetitive and can be done recursively.

Sample calculation using the left shift operator (<<):

10 << 3 = 10 * 2^3 = 10 * 8 = 80
-32 << 2 = -32 * 2^2 = -32 * 4 = -128
5 << 2 = 5 * 2^2 = 5 * 4 = 20

Write a recursive function that mimics (without the use of <<) the left shift operator and returns the result from the two given integers.

Examples

shift_to_left(5, 2) ➞ 20

shift_to_left(10, 3) ➞ 80

shift_to_left(-32, 2) ➞ -128

shift_to_left(-6, 5) ➞ -192

shift_to_left(12, 4) ➞ 192

shift_to_left(46, 6) ➞ 2944

Notes

• There will be no negative values for the second parameter y.
• This challenge is more like recreating of the left shift operation, thus, the use of the operator directly is prohibited.
• You are expected to solve this challenge via recursion.
• An iterative version of this challenge can be found via this link.