Problem of the Day
A new programming or logic puzzle every Mon-Fri

Magic Square

A magic square is an NxN grid where all columns, rows, and diagonals add to the same number. In the case of diagonals on top corner to opposite bottom corner count. Can you create a function that takes in an NxN array and returns if that array is a magic square or not? An example of a 3x3 magic square is below:

4  9  2
3  5  7
8  1  6

Permalink: http://problemotd.com/problem/magic-square/

Comments:

  • Jared DiCioccio - 8 years, 11 months ago

    Quick and dirty python

    def magicSquareTest(grid):
    return (rowsPass(grid) and colsPass(grid) and diagsPass(grid))

def colsPass(grid): 
    return rowsPass(transpose(grid))

def diagsPass(grid):
    return rowsPass(getDiagRows(grid))

def rowsPass(grid):
    return len({(sum(row)) for row in grid})==1

def getDiagRows(grid):  
    r1 = list()
    r2 = list()
    length=len(grid)-1
    for i in range(length+1):
        r1.append(grid[i][i])
        r2.append(grid[i][length-i])
    return [r1,r2]

def transpose(grid):
    return list(map(list,zip(*grid)))

if __name__=='__main__':
    grid1 = [[4, 9, 2], [3, 5, 7], [8, 1, 6]]
    grid2 = [[4, 9, 2], [3, 1, 7], [8, 1, 6]]       
    print(magicSquareTest(grid))
    print("Testing grid: ")
    print(grid1)
    print(magicSquareTest(grid1))
    print("Testing grid: ")
    print(grid2)
    print(magicSquareTest(grid2))

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  • Max Burstein - 8 years, 11 months ago

    Nicely done!

    reply permalink

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