找k個最小值，基本思路是對陣列排序，輸出前k個或者後k個，我們回顧一下之前的學習過的集中排序方法：

1. 快速排序

class Solution():
	def GetLeastNumbers_Solution(self, tinput,k):
		def quick_sort(lis)
 			if not lis:
 				return []
 			q=lis[0]
 			left=quick_sort([x for x in lis[i:] if x<q])
 			right=quick_sort([x for x in lis[1:]if x>q])
 			return left+[q]+right
 		if k > len(tinput):
            return []
        tinput = quick_sort(tinput)
        return tinput[: k]
 

2. 氣泡排序

class Solution():
	def GetLeastNumbers_Solution(self,tinput,k):
		def bubble_sort(lis):
			if not lis:
				return []
			for i in range(len(lis)):
				for j in range(len(lis)-i):
					if lis[j-1]>lis[j]:
						lis[j-1],lis[j]=lis[j],lis[j-1]
			return lis
		if k>len(tinput):
			return []
		tinput=bubble_sort(tinput)
		return tinput[:k]
 

3. 選擇排序

class Solution():
	def GetLeastNumbers_Solution(self,tinput,k):
		def select_sort(lis):
			if lis=[]:
				return []
			for i  in range(len(lis)-1):
				smalllist=i
				for j in range(i,len(lis)):
					if lis[j]<lis[smallest]:
						smallest=j
						lis[j],lis[smallest]=lis[smallest],lis[j]
			return lis

		if  k>len(tinput):
			return []
		tinput=select_sort(tinput)
		return tinput[:k]			
 

4. 插入排序

class Solution():
	def GetLeastNumbers_Solution(self,tinput,k):
		def insert_sort(lis):
			if lis=[]:
				return []
			for i  in range(1,len(lis)):
				for  j  in range(i,0,-1):
					if lis[j]<lis[j-1]:
						lis[j-1],lis[j]=lis[j],lis[j-1]
			return lis
		if k>len(tinput):
			return []
		tinput=insert_sort(tinput)
		return tinput[:k]