Take a positive integer n as input, and output a n-by-n checkerboard matrix consisting of 1 and 0.
The top left digit should always be 1.
Test cases:
n = 1
1
n = 2
1 0
0 1
n = 3
1 0 1
0 1 0
1 0 1
n = 4
1 0 1 0
0 1 0 1
1 0 1 0
0 1 0 1
Input and output formats are optional. Outputting the matrix as a list of lists is accepted.