quicksort

问题 I've noticed a discrepancy in the way quicksort is called recursively. One way is quicksort(Array, left, right) x = partition(Array, left, right) quicksort(Array, left, x-1) quicksort(Array, x+1, right) partition(array, left, right) pivotIndex := choose-pivot(array, left, right) pivotValue := array[pivotIndex] swap array[pivotIndex] and array[right] storeIndex := left for i from left to right - 1 if array[i] ≤ pivotValue swap array[i] and array[storeIndex] storeIndex := storeIndex + 1 swap

问题 I access object properties with an index number object = {} object.y = {60,20,40} object.g = {box1,box2,box3} -- graphic object.c = {false,false,false} -- collision -- object.y[2] is 20 and its graphic is box2 -- sorted by y location, index should be, object.sort = {2,3,1} I know table.sort sorts a list, but how can I sort the y list that returns index for the purpose of drawing each object in-front depending on the y location. Maybe the quicksort function can be edited, I don't understand it

问题 I'm trying to trace this quick sort algorithm: https://pythonschool.net/data-structures-algorithms/quicksort/ But with a different set of numbers - [6,2,8,4,3,7,10] I'm fine once the left side of the algorithm is sorted, but I don't understand the recursion class after that. Once the left side is completed and start = 0 and end = 0 , the following line runs: quicksort(myList, pivot+1, end) When I print out the start and end values from the quick sort function: Start = 2 and End = 1 Start = 3

问题 I just started learning Scheme (Petite Chez Scheme) and as a challenge to myself I'm trying to implement quicksort. However I get the following exception when I run it: Exception: attempt to apply non-procedure (1 2 3 4 5 7 ...) Here's my Scheme session from Emacs: Petite Chez Scheme Version 8.4 Copyright (c) 1985-2011 Cadence Research Systems > (define (set a i k) (define (reduce-list a i n) (if(= i n) a (reduce-list (cdr a) (+ i 1) n))) (if(= i 0) (cons k (cdr a)) (let ((b (cons k (reduce

问题 I am getting an error of "FATAL ERROR: CALL_AND_RETRY_0 Allocation failed - process out of memory" on my Javascript code. How could I run this code? I see no flaws in the code, because I was doing exactly the same thing as in Python and it works in Python, but here in Javascript I am getting memory errors. Below is my code. var sample_arr = [-1, 5, 7, 4, 0, 1, -5] function My_Partition(container, first_index, last_index) { var x = container[last_index]; var i = first_index - 1; for (var elem

问题 The following is my code: #include <stdlib.h> #include <stdio.h> #include <limits> #define INFINITY std::numeric_limits<float>::infinity() #define NEGINFINITY -std::numeric_limits<float>::infinity() int floatcomp(const void* elem1, const void* elem2) { if (*(const float*)elem1 < *(const float*)elem2) return -1; return *(const float*)elem1 > *(const float*)elem2; } int main() { float array[10] = {INFINITY, 3.5f, 144.4f, NAN, 12.4f, NEGINFINITY, 1.4f, -0.0f, 5.9f}; int i; for (i = 0; i < 10; i+

问题 This question is unlikely to help any future visitors; it is only relevant to a small geographic area, a specific moment in time, or an extraordinarily narrow situation that is not generally applicable to the worldwide audience of the internet. For help making this question more broadly applicable, visit the help center. Closed 8 years ago . This is what I have and it doesn't work. Can't figure out why... The problem is probably in the quick_sort function. #include <stdio.h> #include <stdlib

问题 I have several sorted sequences of numbers of type long (ascending order) and want to generate one master sequence that contains all elements in the same order. I look for the most efficient sorting algorithm to solve this problem. I target C#, .Net 4.0 and thus also welcome ideas targeting parallelism. Here is an example: s1 = 1,2,3,5,7,13 s2 = 2,3,6 s3 = 4,5,6,7,8 resulting Sequence = 1,2,2,3,3,4,5,5,6,6,7,7,8,13 Edit: When there are two (or more) identical values then the order of those

问题 This is my quicksort Code. It gives me a wrong answer but i think my partition function is correct. public class Quick_Sort { public static void main(String[] args) { int a[] = {99,88,5,4,3,2,1,0,12,3,7,9,8,3,4,5,7}; quicksort(a, 0, a.length-1); } static int partition(int[] a, int low , int hi) { int pivot = hi; int i =low; int j = hi-1; while(i<j) { if(a[i]<=a[pivot]) { i++; } if(a[i]>a[pivot]) { if((a[i]>a[pivot]) && (a[j]<=a[pivot])) { int temp= a[i]; a[i]=a[j]; a[j]=temp; i++; } if(a[j]>a

问题 I admit my knowledge of algorithms isn't very good. I wrote a quicksort function in R using basic recursion. My question is, how do I modify this algorithm to also display the intermediate vectors between each iteration. I know there is a clever way to do it with tracking where your pivot is but I'm struggling to figure it out myself. qs <- function(vec) { if(length(vec) > 1) { pivot <- vec[1] low <- qs(vec[vec < pivot]) mid <- vec[vec == pivot] high <- qs(vec[vec > pivot]) c(low, mid, high)