快速排序實現

1.結束條件: low = high

2.快速排序要分而治之。故需要分的位置，位置便是當前元素經過排列後應該所在的位置。

3.對於單次的排列，都使得一個元素排在了正確的位置，她的左面比她小，右側比她大。

package com.jue.quicksort;public class Quicksort {/** * @param args */public static void main(String[] args) {// TODO Auto-generated method stubint data[] = { 8, 3, 7, 1, 5, 6, 4, 9, 2 };logs("old : ", data);quickSort(data, 0, data.length - 1);logs("new : ", data);}static void logs(String str, int[] data) {StringBuffer sb = new StringBuffer(str);for (int value : data) {sb.append(value + " ");}System.out.println(sb);}public static void quickSort(int[] data, int low, int high) {if (low >= high) {return;}int index = getSortedIndex(data, low, high);quickSort(data, low, index - 1);quickSort(data, index + 1, high);}private static int getSortedIndex(int[] data, int low, int high) {int currentData = data[low];int currentDataIndex = low;while (low < high) {if (currentDataIndex == low) {if (currentData > data[high]) {data[low] = data[high];data[high] = currentData;currentDataIndex = high;low++;} else if (currentData <= data[high]) {high--;}} else if (currentDataIndex == high) {// move to leftif (currentData < data[low]) {//data[high] = data[low];data[low] = currentData;currentDataIndex = low;high--;} else if (currentData >= data[low]) {low++;}}}return currentDataIndex;}}