获取数组中所有的子数组－Swift3.0 实现

在最大子数组问题中，涉及到暴力求解，那么，如何获取所有的子数组，写了个例子：
ListSubArray.swift如下：

//1 2 3 12 13 23 123

let a = [1, 2, 3]
var subArray = [Any]()

for i in 1...a.count {
    print("list \(i) length sub array")
    print("")
    
    for left in 0..

Terminal运行swift ListSubArray.swift可得到：

list 1 length sub array

left is 0 and right is 1
[1]
left is 1 and right is 2
[2]
left is 2 and right is 3
[3]

list 2 length sub array

left is 0 and right is 2
[1, 2]
left is 1 and right is 3
[2, 3]

list 3 length sub array

left is 0 and right is 3
[1, 2, 3]

count is 6 All subArray is [ArraySlice([1]), ArraySlice([2]), ArraySlice([3]), ArraySlice([1, 2]), ArraySlice([2, 3]), ArraySlice([1, 2, 3])]