heapsort

问题 So I was going through different sorting algorithms. But almost all the sorting algorithms require 2 loops to sort the array. The time complexity of Bubble sort & Insertion sort is O(n) for Best case but is O(n^2) as worst case which again requires 2 loops. Is there a way to sort an array in a single loop? 回答1: Here, a single-loop Bubble Sort in Python: def bubbly_sortish(data): for _ in xrange(len(data)**2): i, j = _/len(data), _%len(data) if i<j and data[i] > data[j]: data[i], data[j] =

问题 Heap Sort has a worst case complexity of O(nlogn) while Quicksort has O(n^2) . But emperical evidences say quicksort is superior. Why is that? 回答1: One of the major factors is that quicksort has better locality of reference -- the next thing to be accessed is usually close in memory to the thing you just looked at. By contrast, heapsort jumps around significantly more. Since things that are close together will likely be cached together, quicksort tends to be faster. However, quicksort's worst

问题 Both quicksort and heapsort do in-place sorting. Which is better? What are the applications and cases in which either is preferred? 回答1: This paper has some analysis. Also, from Wikipedia: The most direct competitor of quicksort is heapsort. Heapsort is typically somewhat slower than quicksort, but the worst-case running time is always Θ(nlogn). Quicksort is usually faster, though there remains the chance of worst case performance except in the introsort variant, which switches to heapsort

问题 Both quicksort and heapsort do in-place sorting. Which is better? What are the applications and cases in which either is preferred? 回答1: This paper has some analysis. Also, from Wikipedia: The most direct competitor of quicksort is heapsort. Heapsort is typically somewhat slower than quicksort, but the worst-case running time is always Θ(nlogn). Quicksort is usually faster, though there remains the chance of worst case performance except in the introsort variant, which switches to heapsort

问题 Who can explain to me exactly how it works next sequence of code. PriorityQueue<Integer> pQueue = new PriorityQueue<Integer>(); for (int w : x) { pQueue.add(w); } for (int k = 0; k < x.length; k++) { x[k] = pQueue.poll(); } // Print the array System.out.println("\nHere is the sorted array with HeapSort:"); for (int w : x) { System.out.print(w + " "); } 回答1: PriorityQueue<Integer> pQueue = new PriorityQueue<Integer>(); This line creates a priority queue of Integers. A priority queue stores a

问题 I have implemented two algorithms for sorting elements from highest to lowest. The first one, takes quadratic time on the real RAM model and the second an O(n log(n)) time. The second one uses priority queues to get the reduction. Here are the timings, which are the output of the above program. the first column is the size of the random array of integers the second column is the time in seconds for the O(n^2) technique the third column is the time in seconds for the O(n log(n)) technique 9600

问题 #include <stdio.h> void Heapify(int num[], int start, int end) { int root = start; while(root*2+1<=end) { // at least one child exists int swap = root; int lchild = root*2+1; int rchild = root*2+2; if(num[swap]<num[lchild]){ swap = lchild; } if(rchild<=end && num[swap]<num[rchild]){ swap = rchild; } if(swap!=root){ // swap here int temp = num[root]; num[root] = num[swap]; num[swap] = temp; root = swap; } else return; } } void buildHeap(int num[]) { int length=sizeof(num)/sizeof(num[0]); int

问题 Functions called: (regardless of class) def partition( pivot, lst ): less, same, more = list(), list(), list() for val in lst: if val < pivot: less.append(val) elif val > pivot: more.append(val) else: same.append(val) return less, same, more def medianOf3(lst): """ From a lst of unordered data, find and return the the median value from the first, middle and last values. """ finder=[] start=lst[0] mid=lst[len(lst)//2] end=lst[len(lst)-1] finder.append(start) finder.append(mid) finder.append

问题 I have been given the task of implementing a heap sort using java. The sorting will be by the annual salary but the object employee will accept both a string for name and an int for salary. I have been successful with bubblesort with basically the same classes but I am having some trouble with the heap sort. Here is my code: import java.util.ArrayList; import java.util.Scanner; public class Company { //create a default heap using array list private ArrayList<Employee> list = new ArrayList

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 6 years ago . I wrote a little C# command application. Four arrays are supposed to be sorted with a heapsort algorithm. I took an algorithm from a website and its running just fine. Now I want to count the key-comparisons the algorithm needs to sort one array. I tried to count the comparisons via for loop but its seems to be