常见排序的JAVA实现和性能测试

/*
* Sort.java
* Version 1.0.0
* Created on 2017年4月27日
* Copyright ReYo.Cn
*/
package reyo.sdk.utils.test.map;

import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;

public class Sort {
	public static void main(String[] args) throws NoSuchMethodException, SecurityException, IllegalAccessException, IllegalArgumentException, InvocationTargetException {
		Sort s1 = new Sort();
		System.out.println("少量数据");
		int arraySize = 200;
		s1.test("insertionSort", arraySize);
		s1.test("bubbleSort", arraySize);
		s1.test("shellSort", arraySize);
		s1.test("heapSort", arraySize);
		s1.test("mergeSort", arraySize);
		s1.test("quickSort", arraySize);
		System.out.println("大量数据");
		arraySize = 50000;
		s1.test("insertionSort", arraySize);
		s1.test("bubbleSort", arraySize);
		s1.test("shellSort", arraySize);
		s1.test("heapSort", arraySize);
		s1.test("mergeSort", arraySize);
		s1.test("quickSort", arraySize);
	}

	// 测试的脚手架
	public void test(String methodName, int size) throws NoSuchMethodException, SecurityException, IllegalAccessException, IllegalArgumentException, InvocationTargetException {
		Method m1 = this.getClass().getMethod(methodName, int[].class);
		int[] test1 = new int[size];
		int[] test2 = new int[size];
		int[] test3 = new int[size];
		int[] test4 = new int[size];
		Sort sorttest = new Sort();
		// 正序
		for (int i = 0; i < size; i++) {
			test1[i] = i;
		}
		// 倒序
		for (int i = 0; i < size; i++) {
			test2[i] = size - i;
		}
		// 乱序,随机,基本无重复元素
		for (int i = 0; i < size; i++) {
			test3[i] = (int) (Math.random() * size);
		}
		// 大量重复元素
		for (int i = 0; i < size; i++) {
			test4[i] = i + 50 % 50;
		}
		long startTime = System.nanoTime();
		long endTime = System.nanoTime();
		m1.invoke(sorttest, test1);
		startTime = System.nanoTime();
		m1.invoke(sorttest, test1);
		endTime = System.nanoTime();
		System.out.println(methodName + "正序数列:" + (endTime - startTime) + "ns");

		startTime = System.nanoTime();
		m1.invoke(sorttest, test2);
		endTime = System.nanoTime();
		System.out.println(methodName + "倒序数列:" + (endTime - startTime) + "ns");

		startTime = System.nanoTime();
		m1.invoke(sorttest, test3);
		endTime = System.nanoTime();
		System.out.println(methodName + "随机数列:" + (endTime - startTime) + "ns");

		startTime = System.nanoTime();
		m1.invoke(sorttest, test4);
		endTime = System.nanoTime();
		System.out.println(methodName + "周期数列:" + (endTime - startTime) + "ns");

		System.out.println();
	}

	// 插入排序,稳定排序
	// 插入排序由N-1趟排序组成,时间最好O(n),最坏O(n2),平均O(n2)
	// 空间O(1)
	public void insertionSort(int[] nums) {
		int j, p;
		int tmp;
		for (p = 1; p < nums.length; p++) {
			tmp = nums[p];
			for (j = p; j > 0; j--) {
				if (nums[j - 1] > tmp)
					nums[j] = nums[j - 1];
			}
			nums[j] = tmp;
		}
	}

	// 冒泡排序,稳定排序
	// 时间最好O(n),最坏O(n2),平均O(n2)
	// 空间O(1)
	public void bubbleSort(int[] nums) {
		int j, p;
		int tmp;
		// 沉水,大数被移动到尾段
		for (p = 0; p < nums.length - 1; p++) {
			for (j = 0; j < nums.length - 1 - p; j++) {
				if (nums[j] > nums[j + 1]) {
					tmp = nums[j];
					nums[j] = nums[j + 1];
					nums[j + 1] = tmp;
				}
			}
		}
		// //气泡,小数浮动到首段
		// for(p = 0; p < nums.length - 1;p++){
		// for(j = nums.length - 1;j > p;j--){
		// if(nums[j-1] > nums[j]){
		// tmp = nums[j];
		// nums[j] = nums[j-1];
		// nums[j-1] = tmp;
		// }
		// }
		// }
	}

	// 希尔排序(缩小增量排序),不稳定排序
	// 属于插入排序,时间最好O(n),最坏O(n2),平均O(n1.3)
	// 空间O(1)
	public void shellSort(int[] nums) {
		int gap = 1; // 增量
		int i, j;
		int len = nums.length;
		int tmp;
		// 初始增量,shell排序的效率与增量设定有很大关系
		while (gap < len / 3)
			gap = gap * 3 + 1;
		for (; gap > 0; gap /= 3) {
			for (i = gap; i < len; i++) {
				tmp = nums[i];
				for (j = i - gap; j >= 0 && nums[j] > tmp; j -= gap)
					nums[j + gap] = nums[j];
				nums[j + gap] = tmp;
			}
		}
	}

	// 堆排序,不稳定排序
	// 时间 平均2nlogn - O(nlogn)
	// 空间O(1)
	// 排序方式
	// 创建一个堆H[0..n-1]
	// 把堆首（最大值）和堆尾互换
	// 把堆的尺寸缩小1，并调用shift_down(0),目的是把新的数组顶端数据调整到相应位置
	// 重复步骤2，直到堆的尺寸为1
	public void heapSort(int[] nums) {
		int i;
		// 遍历所有结点,对不满足规则节点进行调整
		for (i = nums.length / 2; i >= 0; i--) {
			PercDown(nums, i, nums.length);
		}
		for (i = nums.length - 1; i > 0; i--) {
			int tmp = nums[0];
			nums[0] = nums[i];
			nums[i] = tmp;
			PercDown(nums, 0, i);
		}
	}

	// 调整堆序
	public void PercDown(int[] nums, int i, int length) {
		int child;
		int tmp;

		for (tmp = nums[i]; 2 * i + 1 < length; i = child) {
			child = 2 * i + 1; // 左儿子
			if (child != length - 1 && nums[child + 1] > nums[child])
				child++; // 选出左右子结点中的较大值
			if (tmp < nums[child]) { // 父节点小于子节点,需要进行调整
				nums[i] = nums[child];
			} else
				break;
		}
		nums[i] = tmp;
	}

	// 归并排序
	public void mergeSort(int[] nums) {
		int[] tmpArray = new int[nums.length];
		mSort(nums, tmpArray, 0, nums.length - 1);
	}

	public void mSort(int[] nums, int[] tmps, int left, int right) {
		int center;
		if (left < right) {
			center = (left + right) / 2;
			mSort(nums, tmps, left, center);
			mSort(nums, tmps, center + 1, right);
			merge(nums, tmps, left, center + 1, right);
		}
	}

	// 空间归并
	public void merge(int[] nums, int[] tmps, int lpos, int rpos, int rightEnd) {
		int i, leftEnd, numElements, tmpPos;
		leftEnd = rpos - 1;
		tmpPos = lpos;
		numElements = rightEnd - lpos + 1;
		while (lpos <= leftEnd && rpos <= rightEnd) {
			if (nums[lpos] <= nums[rpos])
				tmps[tmpPos++] = nums[lpos++];
			else
				tmps[tmpPos++] = nums[rpos++];
		}
		while (lpos <= leftEnd)
			tmps[tmpPos++] = nums[lpos++];
		while (rpos <= rightEnd)
			tmps[tmpPos++] = nums[rpos++];
		for (i = 0; i < numElements; i++, rightEnd--)
			nums[rightEnd] = tmps[rightEnd];
	}

	// 快速排序
	// 理论上能保证不出现最坏情况:三数中值分割法
	// 小规模排序,快速排序不如插入排序
	public void quickSort(int[] nums) {
		qSort(nums, 0, nums.length - 1);
	}

	// 递归快速排序
	public void qSort(int[] nums, int left, int right) {
		int i, j;
		int pivot;

		if (left + 3 <= right) { // 至少有4个数
			pivot = median3(nums, left, right);
			i = left;
			j = right - 1;
			while (true) {
				// 先推进索引再判断,而不是先判断再决定要不要推进索引
				// 这样避免了a[i]=a[j]=pivot,导致索引不会被推进,也不会跳出循环
				while (nums[++i] < pivot) {
				}
				while (nums[--j] > pivot) {
				}
				if (i < j) {
					int tmp = nums[i];
					nums[i] = nums[j];
					nums[j] = tmp;
				} else
					break;
			}
			int tmp = nums[i];
			nums[i] = nums[right - 1];
			nums[right - 1] = tmp;
			qSort(nums, left, i - 1);
			qSort(nums, i + 1, right);
		}
		// 少于4个数,不再分割,用插入排序直接排序
		else {
			int k, p;
			int tmp;
			for (p = 1; p < right - left + 1; p++) {
				tmp = nums[left + p];
				for (k = p; k > 0; k--) {
					if (nums[left + k - 1] > tmp)
						nums[left + k] = nums[left + k - 1];
				}
				nums[left + k] = tmp;
			}
		}
	}

	// 分割数组
	public int median3(int[] nums, int left, int right) {
		int center = (left + right) / 2;

		if (nums[left] > nums[center]) {
			int tmp = nums[left];
			nums[left] = nums[center];
			nums[center] = tmp;
		}
		if (nums[left] > nums[right]) {
			int tmp = nums[left];
			nums[left] = nums[right];
			nums[right] = tmp;
		}
		if (nums[center] > nums[right]) {
			int tmp = nums[center];
			nums[center] = nums[right];
			nums[right] = tmp;
		}
		int tmp = nums[center];
		nums[center] = nums[right - 1];
		nums[right - 1] = tmp;
		return nums[right - 1];
	}

}