java版快速排序法
/* * 快速排序是最流行的排序算法,本质上通过把一个数组划分为两个子数组, * 然后递归地调用自身为每一个子数组进行快速排序来实现。 * ArrayIns.java * linzhanghui@gmail.com */ package linzhanghui.quicksort; public class ArrayIns { private long[] theArray; private int nElems; public ArrayIns(int max) { theArray = new long[max]; nElems = 0; } public void insert(long value) { theArray[nElems] = value; nElems++; } public void display() { System.out.print("A="); for(int j=0; j<nElems; j++) System.out.print(theArray[j] + " "); System.out.println(""); } public void quickSort() { recQuickSort(0, nElems-1); } public void recQuickSort(int left, int right) { if(right-left <= 0) return; else { long pivot = theArray[right]; int partition = partitionIt(left, right, pivot); recQuickSort(left, partition-1); recQuickSort(partition+1, right); } } public int partitionIt(int left, int right, long pivot) { int leftPtr = left-1; int rightPtr = right; while(true) { while( theArray[++leftPtr] < pivot) ; while(rightPtr > 0 && theArray[--rightPtr] > pivot) ; if(leftPtr >= rightPtr) break; else swap(leftPtr, rightPtr); } swap(leftPtr, right); return leftPtr; } public void swap(int dex1, int dex2) { long temp = theArray[dex1]; theArray[dex1] = theArray[dex2]; theArray[dex2] = temp; } } /* * 程序随机产生16个2位随机数,显示这16个随机数后,对其进行快速排序并输出。 * linzhanghui@gmail.com */ package linzhanghui.quicksort; public class QuickSortApp { public static void main(String[] args) { int maxSize = 16; ArrayIns arr; arr = new ArrayIns(maxSize); for(int j=0; j<maxSize; j++) { long n = (int)(java.lang.Math.random()*99); arr.insert(n); } arr.display(); arr.quickSort(); arr.display(); } }