题目:输入n个整数，找出其中最小的K个数。例如输入4,5,1,6,2,7,3,8这8个数字，则最小的4个数字是1,2,3,4.
核心代码:
<pre><code>`
func leastMinNumbers(arr:[Int],k:Int) -> [Int] {
var data:[Int] = arr
var result:[Int] = []

    quickSort(arr: &data, low: 0, high: data.count-1)
    
    for i in 0..<k {
        result.append(data[i])
    }
    
    return result
}

func quickSort(arr:inout [Int],low:Int,high:Int) {
    if low > high {
        return
    }
    let middle = partition(arr: &arr, low: low, high: high)
    quickSort(arr: &arr, low: low, high: middle-1)
    quickSort(arr: &arr, low: middle+1, high: high)
}


func partition(arr:inout [Int],low:Int,high:Int) -> Int {
    let root:Int = arr[high]
    var index:Int = low
    
    for i in low..<high {
        if arr[i] < root {
            if i != index {
                swap(&arr[i], &arr[index])
            }
            
            index += 1
        }
    }
    
    if index != high {
        swap(&arr[index], &arr[high])
    }
    return index
}`</code></pre>

测试代码:
<pre><code>`

var searchMin:SearchMin = SearchMin()
var data:[Int] = [4,5,1,6,2,7,3,8]
var k:Int = 4
var result:[Int] = searchMin.leastMinNumbers(arr: data, k: k)
print("FlyElephant---最小的(k)个数---(result)")`</code></pre>