quicksort fortran

Quick SortThe fast sort is a sort algorithm, and the worst-case run time is O (N2) for an input array containing n numbers. Although this worst-case run time is poor, fast sequencing is often the best practical choice for sorting,This is because the average performance is quite good: the expected run time is O (NLGN), and the O (NLGN) notation has a small implied constant factor. In addition, it can be ordered in-place, and can work well in a virtual storage environment.Quick Sort (

/*Description: The code refers to the online code, but the analysis for the individual original, this sticker weight in the description of the idea of fast sorting algorithm and operation process. */Code section: #include#includevoidQuickSort (int* Arr,intStartpos,intendpos) { intI, J; intkey; Key=Arr[startpos]; I=startpos; J=Endpos; while(ij) { while(Arr[j] >= key i//———— 1 sweep from behind until a a[j]Arr[i] =Arr[j]; while(Arr[i] //———— 2 sweep from behind until a a[i]>key is found or tra

algorithm, the average time is O (NLGN) for an input array including n, and the worst case is O (n^2).is generally the best choice for sorting. Because, based on the comparison of the sorting, the fastest can only reach O (NLGN).Descriptive narration of high-speed sequencing algorithmIntroduction to Algorithms, 7th chapterHigh-speed sequencing is based on split-mode processing,The divide-and-conquer process for a typical subarray A[P...R] is three steps:1. Decomposition:A[p. R] is divided into

Iv. Fast Sorting (Quick sort)Fast sorting is a widely used sort algorithm, which belongs to the Exchange sort class.Ideas:　　Sorting using recursive algorithms for "Divide and conquer"Steps:1) Benchmark case: n=0 or 1, no sorting required, return2) N>1, take an arbitrary element from the array s ν, called the pivot element (pivot)3) split:　　Put all elements larger than ν to the right of V, S1Put the element that is smaller than V to the left of V, S24) quickly sort the left and right two interva

1. PHP Copy Code code as follows: $unsorted = Array (2,4,5,63,4,5,63,2,4,43); function Quicksort ($array) { if (count ($array) = 0) return Array (); $pivot = $array [0]; $left = $right = Array (); for ($i = 1; $i if ($array [$i] $left [] = $array [$i]; Else $right [] = $array [$i]; } Return Array_merge (Quicksort ($left), Array ($pivot),

Core code: Copy Code code as follows: function QuickSort (arr) { If the array has only one number, it returns directly; if (arr.lengthreturn arr; } Find the index value of that number in the middle, and if it's a float, take it down. var centerindex = Math.floor (ARR.LENGTH/2); The value of this number is found according to the index value of the middle number; var centernum = Arr.splice (centerindex,1); Store the numbe

Label: matlab svm Machine Learning 1. First, we need to download a libsvm toolbox, which can be downloaded everywhere. 2. decompress the compressed package. I decompress the package to c: \ Users \ Administrator \ Desktop \ libsvm on the desktop. 3. Open MATLAB and locate it under the following directory: 4. Enter the following code according to the process: > Mex-SetupWelcome to Mex-setup. This utility will help you set upA default compiler. For a list of supported compilers, seeHttp:

1 First we want to download a LIBSVM toolbox where all this can be downloaded to2 We unpacked my decompression on the desktop address C:\USERS\ADMINISTRATOR\DESKTOP\LIBSVM3 Open MATLAB Navigation to the example in the following folderwatermark/2/text/ahr0cdovl2jsb2cuy3nkbi5uzxqvdtaxmdqxnjewmq==/font/5a6l5l2t/fontsize/400/fill/i0jbqkfcma==/ Dissolve/70/gravity/center "height=" "width=" 731 ">4 we enter the following code according to this process>>Mex-setupWelcome to Mex-setup. This utility would

multi-core (multicore), symmetric multiprocessor (SMP), Clustering (Cluster). 1.2 Introduction of typical MPI implementation 1.MPICH Mpich is the most influential and most user-MPI implementation. Mpich is characterized by: Open source; Develop synchronously with MPI standard; Support multiple program multiple data (multiple programs multiple DATA,MPMD) programming and heterogeneous cluster system; Supports the binding of C/n + +, Fortran 77, and

so on. They are all keywords introduced in the C99 standard, but before the C99 standard came out, extended keywords such as _ inline _ and _ complex _ are already available in gnu c. I still remember that when I learned the source code of Linux 0.11 many years ago, I was confused when I saw a lot of _ inline, I don't know why Linus was able to use such advanced language functions in. Later I learned that this is the GNU extension keyword. C language standards include C89 and C99. When using GC

Ruby implements three fast sorting algorithms: I just learned Ruby. It happened that the algorithm teacher encouraged me to write algorithms in unfamiliar languages. I will use Ruby ~~Ruby is really amazing, and many intuitive methods can be used ..... Infinite worship .... While I encountered an invalid multibyte char (US-ASCII) error, the solution is to add a # encoding: UTF-8 at the beginningThis error was asked by someone on stackoverflow. The answer Someone gave is:Write # encoding: UTF-8 o

Space complexity /*** For sort algorithm, it's basic operation is swap two values. So we can compute it's sentence frequency f (n ):* F (n) = n * n = n ^ 2* (At worst situation)* And it's time complexity is:* T (n) = O (f (n) = O (n ^ 2)*** Obviously, It's space complexity is:* S (n) = O (g (n) = O (C) = O (1)* Because it use only constant space whatever n change.*/ /** The totally example source code is here:** (It maybe some fault, I will gglad to your advices)*/ 3. Quick sort /***** Quick S

left of the axis Recursive to the right of the axis By performing the algorithm, the value on the left side of the axis will be less than s, and the value on the right side of the axis will be greater than s, so that the left and right sides of the axis are handed back, so that the order can be completed. In the above example, the value on the left side of 41 is smaller than it, and the value on the right is larger than it, so that it is handed back to the sort completion. The specific c

Code Listing 1: Copy the code code as follows: function Quicksort ($STR) { if (count ($str) $key = $str [0];//takes a value, which is later used for comparison; $left _arr=array (); $right _arr=array (); for ($i =1; $i if ($str [$i]$left _arr[]= $str [$i]; Else $right _arr[]= $str [$i]; } $left _arr=quicksort ($left _arr);//recursive; $right _arr=quicksort ($righ

Take a value and compare it with other values. put a small value on the left of the value, a large value on the right of the value, and then follow this method to recursively code 1: The code is as follows: Function quicksort ($ str ){If (count ($ str) $ Key = $ str [0]; // Obtain a value for comparison later;$ Left_arr = array ();$ Right_arr = array ();For ($ I = 1; $ I If ($ str [$ I] $ Left_arr [] = $ str [$ I]; Else $ Right_arr [] =

] =Infinity;//sentinel Value //compare left and right element size varm =0, n =0; for(varK = startleft; K if(leftary[m] Else{ary[k] = rightary[n]; n++; } }}//testConsole.log (quickSort (dataary));//[1, 2, 3, 4, 5, 6, 7, 8, 9]Quick Sort? Fast sorting is one of the fastest sorting algorithms for working with large data sets. Its core idea is "divide and conquer". Set the base value to decompose the data once into different sub-sequences

Void QuickSort (SeqList R, int low, int high) { // Fast sorting of R [low... high] Int pivotPos; // the location of the benchmark record after Division If (low { // Sorting is required only when the Interval Length is greater than 1 Extends TPOs = Partition (R, low, high); // divide R [low... high] QuickSort (R, low, pivotPos-1); // recursively sorts the left Interval Q