package Matrix
func rotate(matrix [][]int) {
n := len(matrix)
downHalf, upHalf := n/2, (n+1)/2
for i := 0; i < downHalf; i++ {
for j := 0; j < upHalf; j++ {
temp := matrix[i][j]
matrix[i][j] = matrix[n-1-j][i]
matrix[n-1-j][i] = matrix[n-1-i][n-1-j]
matrix[n-1-i][n-1-j] = matrix[j][n-1-i]
matrix[j][n-1-i] = temp
}
}
}