Sorting method Summary (i) heap sorting

The maximum heap (binary) sorting is divided into several steps:

1.maxheap (), maintaining the nature of the maximum heap, that is, the value of the node is greater than the value of the child node, time complexity O (LGN)

2.bulid_max_heap (), constructs the largest heap from an unordered array, time complexity O (n)

3.heap_sort (), sorting unordered array, time complexity O (NLGN)

Code has comments

1#include <iostream>2 usingstd::cout;3 4 voidMax_heapify (int*a,intLeninti)5 {6     //array starting with 0, left child for 2i+1, right child for 2i+27     intL=2*i+1, r=2*i+2, largest;8 9     //Select the maximum value, record its pointer to largestTen     if(L<len && a[l]>a[i]) largest=l; One     Elselargest=i; A     if(R<len && a[r]>a[largest]) largest=R; -     if(largest!=i) -     { the{inttemp=a[i];a[i]=a[largest];a[largest]=temp;} -  -         //The node is changed, so it is necessary to heapify the changed nodes. -         //because Heapify is performed after its child node heapify. + max_heapify (a,len,largest); -     } + } A voidBulid_max_heap (int*a,intlen) at { -     //len/2,len/2+1 is a leaf node, not heapify . -      for(inti=len/2; i>=0; i--) max_heapify (a,len,i); - } - voidHeapsort (int*a,intlen) - { in     inttemp; - bulid_max_heap (A,len); to      for(inti=len-1; i>=1; i--) +     { -         //Place the top of the heap (maximum) at the end of the array the{temp=a[0];a[0]=a[i];a[i]=temp;} *          $         //the array length -1,heapify the root node and becomes the largest heapPanax Notoginsenglen--; -Max_heapify (A,len,0); the     } + } A  the  + intMain () - { $     inta[]={ A,8564,445, About,8, Wu,6,4,5,4}; $Heapsort (A,Ten); -      for(intI=0;i<Ten; i++) cout<<a[i]<<"  "; -  the     return 0; -}

Sorting method Summary (i) heap sorting