Rotate MXN matrix clockwise by 90 degree

Question: Rotate MXN matrix clockwise by 90 degree

Approach:

Observation

first row of source ------> last column of destination
second row of source ------> last but-one column of destination
so ... on
last row of source ------> first column of destination

n = number of rows and columns (rows==columns, square matrix)
i = line
j = column
a[ ][ ] and b[ ][ ] = the matrixes

And the instructions:

for(i=0; i<m; i++)
                    for(j=0; j<n; j++)
                           b[j][m-i-1]=a[i][j];

Solution:

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18

public int[][] rotateMatrix(int[][] a, int m, int n) {   int[][] b = new int[m][n];   for(int i=0; i<m; i++) {   for(int j=0; j<n; j++) {   b[j][m-i-1] = a[i][j];   }   }   return b;   }