java版快速排序

Java非遞歸方式實現快速排序

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package sort.algorithm; import java.util.Stack; //快速排序的非遞歸實現，利用系統的棧stack public class QuickSortNonRecursion {      public static void main(String[] args) {          QuickSortNonRecursion qsnr = new QuickSortNonRecursion();          int[] array = {0, 2, 11, 121, 18, 99, 3, 5, 101, 22, 9, 100};          qsnr.quicksort(array);           for (int i : array) {                 System.out.print(i + "  ");           }         }                           public void quicksort(int[] array) {             if (array == null || array.length == 1) return;             //存放開始與結束索引             Stack<Integer> s = new Stack<Integer>();              //壓棧                    s.push(0);              s.push(array.length - 1);              //利用循環裏實現             while (!s.empty()) {                  int right = s.pop();                  int left = s.pop();                  //如果最大索引小於等於左邊索引，說明結束了                 if (right <= left) continue;                                            int i = partition(array, left, right);                  if (left < i - 1) {                     s.push(left);                     s.push(i - 1);                 }                  if (i + 1 < right) {                     s.push(i+1);                     s.push(right);                 }             }          }         //找到軸心，進行交換         public int partition (int[] data, int first, int end)         {             int temp;             int i=first,j=end;             if(first<end)             {                 temp=data[i];                 //當i=j的時候，則說明掃描完成了                 while(i<j)                 {                     //從右邊向左邊掃描找到一個小於temp的元素                     while(j>i&&data[j]>temp)j--;                     if(i<j)                     {                         //將該元素賦值給temp                         data[i]=data[j];                         //賦值後就應該將i+1指向下一個序號                         i++;                     }                                                 //然後從左邊向右邊開始掃描，找到一個大於temp的元素                     while(i<j&&temp>data[i])i++;                     if(i<j)                     {                         //將該元素賦值給temp                         data[j]=data[i];                         //賦值後就應該將j-1指向前一個序號                         j--;                     }                 }                 //將軸數據放在i位置中                 data[i]=temp;             }             return i;         }     }