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);
}
}
}