20191014：快速排序1.2

描述

昨天的文章提到了參考點的選擇是快速排序法的效率關鍵之一，在這邊的快速排序法的軸選擇方式更加快了快速排序法的效率。

代碼實現

C++實現：

// QuickPartition.cpp : 定義控制檯應用程序的入口點。
//

#include "stdafx.h"
#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#define MAX 10
#define SWAP(x,y) {int t; t = x; x = y; y = t;}
int partition(int[], int, int);
void quicksort(int[], int, int);
int main(void) {
	int number[MAX] = {0};
	int i, num;
	srand(time(NULL));
	printf("排序前：");
	for(i = 0; i < MAX; i++) {
		number[i] = rand() % 100;
		printf("%d ", number[i]);
	}
	quicksort(number, 0, MAX-1);
	printf("\n排序後：");
	for(i = 0; i < MAX; i++)
		printf("%d ", number[i]);
	printf("\n");
	return 0;
}
int partition(int number[], int left, int right) {
	int i, j, s;
	s = number[right];
	i = left - 1;
	for(j = left; j < right; j++) {
		if(number[j] <= s) {
			i++;
			SWAP(number[i], number[j]);
		}
	}
	SWAP(number[i+1], number[right]);
	return i+1;
}
void quicksort(int number[], int left, int right) {
	int q;
	if(left < right) {
		q = partition(number, left, right);
		quicksort(number, left, q-1);
		quicksort(number, q+1, right);
	}
}

Java實現：

package com.immunize.Arithmetic;

/**
 * Quick排序1.2
 * 
 * @author Mr IMMUNIZE
 *
 */
public class QuickPartition {

	public static void main(String[] args) {
		int[] arr = { 1, 3, 5, 2, 22, 13, 6, 78, 65 };
		QuickSort2(arr, 0, arr.length - 1);
		Print(arr);

	}

	public static int partition(int[] number, int left, int right) {
		int i, j, s, tmp;
		s = number[right];
		i = left - 1;
		for (j = left; j < right; j++)
			if (number[j] <= number[right]) {
				i++;
				tmp = number[i];
				number[i] = number[j];
				number[j] = tmp;
			}
		tmp = number[i + 1];
		number[i + 1] = number[right];
		number[right] = tmp;

		return i + 1;
	}

	public static void QuickSort2(int[] number, int left, int right) {
		int q;
		if (left < right) {
			q = partition(number, left, right);
			QuickSort2(number, left, q - 1);
			QuickSort2(number, q + 1, right);
		}

	}

	public static void Print(int[] number) {
		for (int i = 0; i < number.length; i++) {
			System.out.print(number[i] + " ");
		}
		System.out.println();
	}
}