题目描述
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,。
方法一：蒂姆排序
# -*- coding:utf-8 -*-
class Solution:
def GetLeastNumbers_Solution(self, tinput, k):
# write code here
a = sorted(tinput)
if len(a)<k:
return []
else:
return a[:k]
方法二：快速排序
# -*- coding:utf-8 -*-
class Solution:
def GetLeastNumbers_Solution(self, tinput, k):
# write code here
def quick_sort(lst):
if not lst:
return []
pivot = lst[0]
left = quick_sort([x for x in lst[1: ] if x < pivot])
right = quick_sort([x for x in lst[1: ] if x >= pivot])
return left + [pivot] + right
if tinput == [] or k > len(tinput):
return []
tinput = quick_sort(tinput)
return tinput[: k]
方法三：归并排序
# -*- coding:utf-8 -*-
class Solution:
def GetLeastNumbers_Solution(self, tinput, k):
# write code here
def merge_sort(lst):
if len(lst) <= 1:
return lst
mid = len(lst) // 2
left = merge_sort(lst[: mid])
right = merge_sort(lst[mid:])
return merge(left, right)
def merge(left, right):
l, r, res = 0, 0, []
while l < len(left) and r < len(right):
if left[l] <= right[r]:
res.append(left[l])
l += 1
else:
res.append(right[r])
r += 1
res += left[l:]
res += right[r:]
return res
if tinput == [] or k > len(tinput):
return []
tinput = merge_sort(tinput)
return tinput[: k]
方法四：堆排序
# -*- coding:utf-8 -*-
class Solution:
def GetLeastNumbers_Solution(self, tinput, k):
# write code here
def siftup(lst, temp, begin, end):
if lst == []:
return []
i, j = begin, begin * 2 + 1
while j < end:
if j + 1 < end and lst[j + 1] > lst[j]:
j += 1
elif temp > lst[j]:
break
else:
lst[i] = lst[j]
i, j = j, 2 * j + 1
lst[i] = temp
def heap_sort(lst):
if lst == []:
return []
end = len(lst)
for i in range((end // 2) - 1, -1, -1):
siftup(lst, lst[i], i, end)
for i in range(end - 1, 0, -1):
temp = lst[i]
lst[i] = lst[0]
siftup(lst, temp, 0, i)
return lst
if tinput == [] or k > len(tinput):
return []
tinput = heap_sort(tinput)
return tinput[: k]
方法五：冒泡排序
在这里插入代码片
方法六：直接选择排序
在这里插入代码片
方法七：插入排序
在这里插入代码片
