双螺旋矩阵的定义如下，矩阵的最中心是1，往上是2，右拐3，向下4，然后依次5、6，7...构成一条顺序增大的螺旋线，此外，如果从中心往下走的话，也是一条对称的螺旋线。题目是给定一个矩阵维度N，将其打印出来

-Double helix is defined as the matrix, the matrix is 1, up 2, right 3, down 4, to be followed by a sequence 5,6,7 ... constitute the helix increases, in addition, if Center, then go down as well as a symmetrical spiral. The subject is given a matrix dimension of N, to print out