STL source code profiling algorithm stl_algo.h -- merge sort

STL source code profiling algorithm stl_algo.h -- merge sort

 

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Description: Merge Sorting.
Ideas:
1. Semi-segmentation of intervals
2. Sort the Left and Right segments separately
3. Use inplace_merge to merge left and right segments into a complete ordered sequence


Complexity: O (nlog n)
Source code:

Template

 
  
Void mergesort (BidirectionalIter first, BidirectionalIter last) {typename iterator_traits

  
   
: Diference_type n = distance (first, last); if (n = 0 | n = 1) return; else {BidirectionalIter mid = first + n/2; mergesort (first, mid); mergesort (mid, last); inplace_merge (first, mid, last );}}

  

 

Example:

 

Int main () {int a [] = {, 9, 9 }; int * a_end = a + sizeof a/sizeof (int); std: cout <''; mergesort (a, a_end); std :: cout <); std: cout <''; return 0 ;}