func spiralOrder(matrix [][]int) []int {
	totalColumn := len(matrix)
	if totalColumn == 0 {
		return make([]int, 0)
	}
	totalRows := len(matrix[0])

	resultSlice := make([]int, totalColumn*totalRows)

	currentIndex := 0
	swirlOnce := func(cStartIndex int, cEndIndex int, rStartIndex int, rEndIndex int, appendSlice *[]int) bool {

		for i := rStartIndex; i <= rEndIndex; i++ {
			(*appendSlice)[currentIndex] = matrix[cStartIndex][i]
			currentIndex += 1
		}

		if cStartIndex+1 > cEndIndex {
			return false
		}

		//down
		for i := cStartIndex + 1; i <= cEndIndex; i++ {
			(*appendSlice)[currentIndex] = matrix[i][rEndIndex]
			currentIndex += 1
		}

		if rEndIndex-1 < rStartIndex {
			return false
		}

		//left
		for i := rEndIndex - 1; i >= rStartIndex; i-- {
			(*appendSlice)[currentIndex] = matrix[cEndIndex][i]
			currentIndex += 1
		}

		if cEndIndex-1 <= cStartIndex {
			return false
		}

		//up
		for i := cEndIndex - 1; i > cStartIndex; i-- {
			(*appendSlice)[currentIndex] = matrix[i][rStartIndex]
			currentIndex += 1
		}
		return true
	}

	totalSwirlCount := totalRows / 2
	if totalSwirlCount*2 != totalRows {
		totalSwirlCount += 1
	}

	for i := 0; i < totalSwirlCount; i++ {
		hasNext := swirlOnce(i, totalColumn-1-i, i, totalRows-1-i, &resultSlice)
		if !hasNext {
			break
		}

	}
	return resultSlice
}