Matrix 90° clockwise rotation (in place algorithm)

main.go

func invertArrayInPlace(array []int) []int {
	for c := range array[:len(array)/2] {
		temp := array[c]
		array[c] = array[len(array)-c-1]
		array[len(array)-1-c] = temp
	}
	return array
}

func InvertRows(matrix [][]int) [][]int {
	for i, r := range matrix {
		matrix[i] = invertArrayInPlace(r)
	}
	return matrix
}

func Transpose(matrix [][]int) [][]int {
	for i := 0; i < len(matrix); i++ {
		for j := i + 1; j < len(matrix); j++ {
			temp := matrix[i][j]
			matrix[i][j] = matrix[j][i]
			matrix[j][i] = temp
		}
	}
	return matrix
}

func RotateClockwiseIP(matrix [][]int, deg int) [][]int {
	matrix = Transpose(matrix)
	matrix = InvertRows(matrix)
	return matrix
}