mergesort

问题 Note: This post was completely rewritten 2011-06-10; thanks to Peter for helping me out . Also, please don't be offended if I don't accept one answer, since this question seems to be rather open-ended. (But, if you solve it, you get the check mark, of course). Another user had posted a question about parallelizing a merge sort. I thought I'd write a simple solution, but alas, it is not much faster than the sequential version. Problem statement Merge sort is a divide-and-conquer algorithm,

问题 #include<stdio.h> #include<stdlib.h> typedef struct points{ float axis[2]; int id; }Points; typedef enum{ SortById, SortByXAxis }SortType; Points* fill_Array(char* filename, int* length); void Print_set(Points* set, int number_of_points); void mergesort(Points* set, int low, int high, int number_of_points,SortType sort); void merge(Points* set, int low, int middle, int high, int number_of_points,SortType sort); int main(int argc, char* argv[]) { int length; Points *array; array=fill_Array

问题 Closed. This question is off-topic. It is not currently accepting answers. Want to improve this question? Update the question so it's on-topic for Stack Overflow. Closed 5 years ago . I have made a merge sort program in Python and it is running perfectly but I have modified it to count the number of inversions involved and now it is giving me an error : Here's my code: def merge_list(left,right,c): result=[] i,j=0,0 while i < len(left) and j < len(right): if left[i] < right[j]: result.append

问题 I'm learning algorithms from Cormen and Co. and I have problem with implementation of merge sort from their pseudocode. I compiled it by: $ gcc -Wall -g merge_sort.c I have a problem because for numbers: 2 4 5 7 1 2 3 6 The result is: 1 2 2 3 3 4 5 5 I tried to read carefully the pseudo code but this does not help me. I want to know what I'm doing wrong. Below is my code: #include <stdio.h> #define SIZE 8 void merge(int *array_of_integers, int p, int q, int r) { int n1 = q - p + 1; int n2 = r

问题 I'm having some troubles understanding this behaviour. I'm measuring the execution time with the timeit-module and get the following results for 10000 cycles: Merge : 1.22722930395 Bubble: 0.810706578175 Select: 0.469924766812 This is my code for MergeSort: def mergeSort(array): if len(array) <= 1: return array else: left = array[:len(array)/2] right = array[len(array)/2:] return merge(mergeSort(left),mergeSort(right)) def merge(array1,array2): merged_array=[] while len(array1) > 0 or len

问题 I'm having some troubles understanding this behaviour. I'm measuring the execution time with the timeit-module and get the following results for 10000 cycles: Merge : 1.22722930395 Bubble: 0.810706578175 Select: 0.469924766812 This is my code for MergeSort: def mergeSort(array): if len(array) <= 1: return array else: left = array[:len(array)/2] right = array[len(array)/2:] return merge(mergeSort(left),mergeSort(right)) def merge(array1,array2): merged_array=[] while len(array1) > 0 or len

问题 Most of the mergesort implementations I see are similar to this. intro to algorithms book along with online implentations I search for. My recursion chops don't go much further than messing with Fibonacci generation (which was simple enough) so maybe it's the multiple recursions blowing my mind, but I can't even step through the code and understand whats going on even before I even hit the merge function. How is it stepping through this? Is there some strategy or reading I should undergo to

问题 I'am doing a report about different sorting algorithms in C++. What baffles me is that my mergesort seems to be slower than heapsort in both of the languages. What I've seen is that heapsort is supposed to be slower. My mergesort sorts an unsorted array with size 100000 at a speed of 19.8 ms meanwhile heapsort sorts it at 9.7 ms. The code for my mergesort function in C++ is as follows: void merge(int *array, int low, int mid, int high) { int i, j, k; int lowLength = mid - low + 1; int

问题 It's difficult to tell what is being asked here. This question is ambiguous, vague, incomplete, overly broad, or rhetorical and cannot be reasonably answered in its current form. For help clarifying this question so that it can be reopened, visit the help center. Closed 7 years ago . Found this coded mergesort on http://www.explainth.at/en/delphi/dsort.shtml (site down but try wayback machine or this site: http://read.pudn.com/downloads192/sourcecode/delphi_control/901147/Sorts.pas__.htm) but

问题 This generates a Segmentation Fault: 11 and I have no clue why. Before I get into it, here's the code: import numpy.random as nprnd import heapq import sys sys.setrecursionlimit(10**6) def rlist(size, limit_low, limit_high): for _ in xrange(size): yield nprnd.randint(limit_low, limit_high) def iterator_mergesort(iterator, size): return heapq.merge( iterator_mergesort( (iterator.__next__ for _ in xrange(size/2)), size/2), iterator_mergesort( iterator, size - (size/2)) ) def test(): size = 10*