public static void rotate(int[][] matrix) {

int tR = 0;

int tC = 0;

int dR = matrix.length - 1;

int dC = matrix[0].length - 1;

while (tR < dR) {

rotateEdge(matrix, tR++, tC++, dR--, dC--);

}

}

public static void rotateEdge(int[][] m, int tR, int tC, int dR, int dC) {

int times = dC - tC;

int tmp = 0;

for (int i = 0; i != times; i++) {

tmp = m[tR][tC + i];

m[tR][tC + i] = m[dR - i][tC];

m[dR - i][tC] = m[dR][dC - i];

m[dR][dC - i] = m[tR + i][dC];

m[tR + i][dC] = tmp;

}

}

public static void printMatrix(int[][] matrix) {

for (int i = 0; i < matrix.length; i++) {

for (int j = 0; j < matrix[0].length; j++){

System.out.print(matrix[i][j] + " ");

}

System.out.println();

}

}

public static void main(String[] args) {

int[][] matrix = {{1, 2, 3, 4}, {5, 6, 7, 8}, {9, 10, 11, 12}, {13, 14, 15, 16}};

printMatrix(matrix);

rotate(matrix);

System.out.println("After rotating: ");

printMatrix(matrix);

}

}