Rotate a matrix 90 degrees

rotate.go

// going with the transpose / reverse solution
func rotate(matrix [][]int)  {
    n := len(matrix);

    for i := 0; i<n; i++ {
        for j := i + 1; j < n; j++ {
            matrix[i][j], matrix[j][i] = matrix[j][i], matrix[i][j]
        }
    }
    for i := 0; i<n; i++ {
        reverse(matrix[i])
    }   
}

func reverse (a []int) {
    for left, right := 0, len(a)-1; left < right; left, right = left+1, right-1 {
        a[left], a[right] = a[right], a[left]
    }    
}