python top k问题

numpy的：

      import numpy as np
      top_k=3
      arr = np.array([1, 3, 2, 4, 5])
      top_k_idx=arr.argsort()[::-1][0:top_k]
      print(top_k_idx)
  
 

      #coding=utf-8
      '''
      Created on Sep 21, 2015
      @author: haoyifen
      '''
      import time
      import random
      def left(i):
       return 2*i+1
      def right(i):
       return 2*i+2
      def min_heapify(a,heap_size,i):
        l=left(i)
        r=right(i)
       if l<heap_size and a[l]<a[i] :
       least=l
       else:
       least=i
       if r<heap_size and a[r]<a[least]:
       least=r
       if least!=i:
       a[i],a[least]=a[least],a[i]
       min_heapify(a, heap_size, least)
      def build_min_heap(a,heap_size):
       for i in range((heap_size-1)//2,-1,-1):
       min_heapify(a, heap_size, i)
      def heap_sort(a,heap_size):
        build_min_heap(a, heap_size)
       for i in range(heap_size-1,0,-1):
       a[i],a[0]=a[0],a[i]
      #print a
       heap_size-=1
       min_heapify(a, hea
  
 

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原文链接：blog.csdn.net/jacke121/article/details/88933119