用Java随机生成10000不含重复的整数,用快速排序对其从小到大排序并记录运行时间(分三种情况:有序,逆序,随机排序),请给出代码实现
时间: 2023-03-29 16:01:28 浏览: 51
以下是Java代码实现:
import java.util.*;
public class QuickSort {
public static void main(String[] args) {
int[] arr = generateRandomArray(10000);
long startTime = System.currentTimeMillis();
quickSort(arr, , arr.length - 1);
long endTime = System.currentTimeMillis();
System.out.println("随机排序运行时间:" + (endTime - startTime) + "ms");
arr = generateOrderedArray(10000);
startTime = System.currentTimeMillis();
quickSort(arr, , arr.length - 1);
endTime = System.currentTimeMillis();
System.out.println("有序排序运行时间:" + (endTime - startTime) + "ms");
arr = generateReverseArray(10000);
startTime = System.currentTimeMillis();
quickSort(arr, , arr.length - 1);
endTime = System.currentTimeMillis();
System.out.println("逆序排序运行时间:" + (endTime - startTime) + "ms");
}
public static int[] generateRandomArray(int n) {
Set<Integer> set = new HashSet<>();
Random random = new Random();
while (set.size() < n) {
set.add(random.nextInt());
}
int[] arr = new int[n];
int i = ;
for (int num : set) {
arr[i++] = num;
}
return arr;
}
public static int[] generateOrderedArray(int n) {
int[] arr = new int[n];
for (int i = ; i < n; i++) {
arr[i] = i;
}
return arr;
}
public static int[] generateReverseArray(int n) {
int[] arr = new int[n];
for (int i = ; i < n; i++) {
arr[i] = n - i - 1;
}
return arr;
}
public static void quickSort(int[] arr, int left, int right) {
if (left >= right) {
return;
}
int pivot = arr[left];
int i = left, j = right;
while (i < j) {
while (i < j && arr[j] >= pivot) {
j--;
}
arr[i] = arr[j];
while (i < j && arr[i] <= pivot) {
i++;
}
arr[j] = arr[i];
}
arr[i] = pivot;
quickSort(arr, left, i - 1);
quickSort(arr, i + 1, right);
}
}