LFSR Step

Problem

Advance a linear feedback shift register by one step. The feedback bit is the XOR of state[i] for every index in taps; the new state is [feedback] followed by the state minus its last bit.

Hint

Each step shifts the register toward the end and injects the feedback at the front.

Test cases

case 1

in: [[1,0,1],[0,2]]

expected: [0,1,0]

case 2

in: [[1,0,0],[1,2]]

expected: [0,1,0]

case 3

in: [[0,1,1,0],[0,3]]

expected: [0,0,1,1]

case 4

in: [[1,1],[0,1]]

expected: [0,1]

Starter codePython

def lfsr_step(state, taps):
    # Your code here
    pass

4 test cases · run your code against them in the editor