java实现递归快排和非递归快排

package sort;

import java.util.Random;

public class QuickSort {
	public static Random random = new Random(1000);

	public static void exchange(int[] array, int i, int j) {
		int temp = array[i];
		array[i] = array[j];
		array[j] = temp;
	}

	public static int getPivot(int[] array, int from, int to) {
		int target = array[to];
		int i = from - 1;
		for (int j = from; j < to; j++) {
			if (array[j] <= target) {
				i++;
				exchange(array, i, j);
			}
		}
		exchange(array, i + 1, to);
		return i + 1;
	}

	public static void insertSort(int[] L, int low, int high) {
		int i, j, temp;
		for (i = low + 1; i <= high; i++) {
			if (L[i] < L[i - 1]) {
				temp = L[i];
				for (j = i - 1; L[j] > temp && j >= low; j--) {
					L[j + 1] = L[j];
				}
				L[j + 1] = temp;
			}
		}
	}

	public static void noQuickSort(int[] array, int from, int to) {
		int stack[] = new int[10000];
		int top = 0;
		int pivot = getPivot(array, from, to);
		int temp = pivot + 1;
		for (int i = pivot + 1; i < to + 1; i++) {
			if (array[i] > array[temp]) {
				temp = i;
			}
		}
		stack[top++] = to;
		stack[top++] = pivot;
		exchange(array, temp, to);
		for (;;) {
			if ((pivot - from) > 20) {
				pivot = getPivot(array, from, pivot - 1);
				stack[top++] = pivot;
			} else {
				insertSort(array, from, pivot - 1);
				from = pivot + 1;
				if (top == 1) {
					break;
				}
				pivot = stack[top - 2];
				top--;
			}
		}
	}

	public static void quickSort(int[] array, int from, int to) {
		if (from < to) {
			int temp = from + (int) (Math.random() * (to - from));
			exchange(array, temp, to);
			int pivot = getPivot(array, from, to);
			quickSort(array, from, pivot - 1);
			quickSort(array, pivot + 1, to);
		}
	}
}