Python：最小的 k 个数

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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,。

# -*- coding:utf-8 -*-'''最小的k个数题目描述输入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,。'''class Solution:# 蒂姆排序：    def GetLeastNumbers_Solution1(self, tinput, k):        # write code here        if tinput == [] or k > len(tinput):            return []        tinput.sort()        return tinput[: k]# 快速排序：    def GetLeastNumbers_Solution2(self, tinput, k):        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]# 归并排序：    def GetLeastNumbers_Solution3(self, tinput, k):        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]# 堆排序：    def GetLeastNumbers_Solution4(self, tinput, k):        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]# 冒泡排序：    def GetLeastNumbers_Solution5(self, tinput, k):        def bubble_sort(lst):            if lst == []:                return []            for i in range(len(lst)):                for j in range(1, len(lst) - i):                    if lst[j-1] > lst[j]:                        lst[j-1], lst[j] = lst[j], lst[j-1]            return lst        if tinput == [] or k > len(tinput):            return []        tinput = bubble_sort(tinput)        return tinput[: k]# 直接选择排序：    def GetLeastNumbers_Solution6(self, tinput, k):        def select_sort(lst):            if lst == []:                return []            for i in range(len(lst)-1):                smallest = i                for j in range(i, len(lst)):                    if lst[j] < lst[smallest]:                        smallest = j                lst[i], lst[smallest] = lst[smallest], lst[i]            return lst        if tinput == [] or k > len(tinput):            return []        tinput = select_sort(tinput)        return tinput[: k]# 插入排序：    def GetLeastNumbers_Solution7(self, tinput, k):        def Insert_sort(lst):            if lst == []:                return []            for i in range(1, len(lst)):                temp = lst[i]                j = i                while j > 0 and temp < lst[j - 1]:                    lst[j] = lst[j - 1]                    j -= 1                lst[j] = temp            return lst        if tinput == [] or k > len(tinput):            return []        tinput = Insert_sort(tinput)        return tinput[: k]