isMagicSquare Solution

public boolean isMagicSquare( int[][] arr ){
    //empty is a magic square
    if( arr.length == 0 ) return true;

    //check all rows have same number of columns as the number of rows
    for( int r = 0; r < arr.length; r++){
        if( arr.length != arr[r].length ) return false;
    }

    //rows
    int[] rowSums = new int[arr.length];
    for(int r = 0; r < arr.length; r++){
        for(int c = 0; c < arr[0].length; c++){
            rowSums[r] += arr[r][c];//store the sum of each row in the 1D array
        }
    }
    for(int r = 0; r < rowSums.length - 1; r++){
        if( rowSums[r] != rowSums[r+1] ) return false;//if any row sums are not equal, return false
    }

    //columns
    int[] colSums = new int[arr[0].length];
    for(int c = 0; c < arr[0].length; c++){
        for(int r = 0; r < arr.length; r++){
            colSums[c] += arr[r][c];//store the sum of each col in the 1D array
        }
    }
    for(int c = 0; c < colSums.length - 1; c++){
        if( colSums[c] != colSums[c+1] ) return false;//if any col sums are not equal, return false
    }

    //diagonals
    //left to right
    int leftDiagSum = 0;
    for( int rowAndCol = 0; rowAndCol < arr.length; rowAndCol++ ){
        leftDiagSum += arr[rowAndCol][rowAndCol];
    }

    //right to left
    int rightDiagSum = 0;
    int x = arr.length - 1;
    for( int rowAndCol = 0; rowAndCol < arr.length; rowAndCol++ ){
        rightDiagSum += arr[rowAndCol][x - rowAndCol];
    }
    if( leftDiagSum != rightDiagSum ) return false;

    return true;
}