面试40题:
题目:最小的k个数
题: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,。
解题思路一:
class Solution:
def GetLeastNumbers_Solution(self, tinput, k):
if k >len(tinput):
return []
tinput.sort()
return tinput[:k]
解题思路二:
class Solution:
def GetLeastNumbers_Solution(self, tinput, k):
# write code here
import heapq
#此方法时间复杂度为O(nlogk)
if k >len(tinput):
return []
return heapq.nsmallest(k,tinput)
解题思路三:
def GetLeastNumbers_Solution(self, tinput, k):
import heapq as hq
if k > len(tinput) or k <= 0: return []
heap = [-x for x in tinput[:k]]
hq.heapify(heap)
for num in tinput[k:]:
if -heap[0] > num:
hq.heapreplace(heap, -num)
return sorted(-x for x in heap)