快速排序

public class QuickSort {

/**
* 划分数组
*/
public static int partition(long arr[],int left, int right,long point) {
int leftPtr = left - 1;
int rightPtr = right;
while(true) {
//循环,将比关键字小的留在左端
while(leftPtr < rightPtr && arr[++leftPtr] < point);
//循环，将比关键字大的留在右端
while(rightPtr > leftPtr && arr[--rightPtr] > point);

if(leftPtr >= rightPtr) {
break;
} else {
long tmp = arr[leftPtr];
arr[leftPtr] =  arr[rightPtr];
arr[rightPtr] = tmp;
}
}
//将关键字和当前leftPtr所指的这一个进行交换
long tmp = arr[leftPtr];
arr[leftPtr] =  arr[right];
arr[right] = tmp;
return leftPtr;
}
public static void sort(long[] arr, int left, int right) {
if(right - left <= 0) {
return;
} else {
//设置关键字
long point = arr[right];
//获得切入点，同时对数组进行划分
int partition = partition(arr, left, right, point);
//对左边的子数组进行快速排序
sort(arr,left,partition - 1);
//对右边的子数组进行快速排序
sort(arr,partition + 1, right);
}
}

public static void displayArr(long[] arr) {
System.out.print("[");
for(long num : arr) {
System.out.print(num + " ");
}
System.out.print("]");
System.out.println();
}

public static void main(String[] args) {
long[] arr = new long[10];
for (int i = 0; i < 10; i++) {
arr[i] = (long)(Math.random()*99);
}
displayArr(arr);

sort(arr, 0, arr.length - 1);

displayArr(arr);
}
}