Count Magic Squares

Problem

Count the 3 by 3 contiguous subgrids of grid that are magic squares: they contain each digit from 1 to 9 exactly once and every row, column and diagonal sums to 15.

Check every possible top-left corner of a 3 by 3 window. Return 0 for grids smaller than 3 by 3.

Hint

A 3 by 3 magic square must be a permutation of 1 through 9 and every line sums to 15.

Test cases

case 1

in: [[[4,3,8,4],[9,5,1,9],[2,7,6,2]]]

expected: 1

case 2

in: [[[8]]]

expected: 0

case 3

in: [[]]

expected: 0

case 4

in: [[[5,5,5],[5,5,5],[5,5,5]]]

expected: 0

case 5

in: [[[4,3,8],[9,5,1],[2,7,6]]]

expected: 1

Starter codePython

def count_magic_squares(grid):
    # Your code here
    pass

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