Java实现冒泡排序与双向冒泡排序算法的代码示例

public class BubbleSort {   public static void main(String[] args) {     int len = 10;     int[] ary = new int[len];     Random random = new Random();     for (int j = 0; j < len; j++) {       ary[j] = random.nextInt(1000);     }        System.out.println("-------排序前------");     for (int j = 0; j < ary.length; j++) {       System.out.print(ary[j] + " ");     }     /*      * 升序， Asc1和Asc2优化了内部循环的比较次数，比较好      * 总的比较次数：      *   Asc1、Asc2：(1+n-1)/2*(n-1) ==> n/2*(n-1) ==> n*(n-1)/2 ==>(n^2-n)/2      *   Asc： n^2-n      */ //   orderAsc(ary); //   orderAsc2(ary);     orderAsc1(ary);          //降序，只需要把判断大小于 置换一下        }      static void orderAsc(int[] ary) {     int count = 0;//比较次数     int len = ary.length;     for (int j = 0; j < len; j++) {//外层固定循环次数       for (int k = 0; k < len - 1; k++) {//内层固定循环次数         if (ary[k] > ary[k + 1]) {           ary[k] = ary[k + 1] + (ary[k + 1] = ary[k]) * 0;//一步交换           /* 交换两个变量值            * a=a+b            * b=a-b            * a=a-b            */         }          count++;       }     }     System.out.println("/n-----orderAsc升序排序后------次数：" + count);     for (int j = 0; j < len; j++) {       System.out.print(ary[j] + " ");     }   }      static void orderAsc1(int[] ary) {     int count = 0;//比较次数     int len = ary.length;     for (int j = 0; j < len; j++) {//外层固定循环次数       for (int k = len - 1; k > j; k--) {//内层从多到少递减比较次数         if (ary[k] < ary[k - 1]) {           ary[k] = ary[k - 1] + (ary[k - 1] = ary[k]) * 0;//一步交换         }          count++;       }     }     System.out.println("/n-----orderAsc1升序排序后------次数：" + count);     for (int j = 0; j < len; j++) {       System.out.print(ary[j] + " ");     }   }    static void orderAsc2(int[] ary) {     int count = 0;//比较次数     int len = ary.length;     for (int j = len - 1; j > 0; j--) {//外层固定循环次数       /*        * k < j; 总的比较次数=(n^2-n)/2        */       for (int k = 0; k < j; k++) {//内层从多到少递减比较次数         if (ary[k] > ary[k + 1]) {           ary[k] = ary[k + 1] + (ary[k + 1] = ary[k]) * 0;//一步交换         }         count++;       }     }     System.out.println("/n-----orderAsc2升序排序后------次数：" + count);     for (int j = 0; j < len; j++) {       System.out.print(ary[j] + " ");     }   } } 

-------排序前------ 898 7 862 286 879 660 433 724 316 737  -----orderAsc1升序排序后------次数：45 7 286 316 433 660 724 737 862 879 898  

public class Bubble_CocktailSort {   public static void main(String[] args) {     int len = 10;     int[] ary = new int[len];     Random random = new Random();     for (int j = 0; j < len; j++) {       ary[j] = random.nextInt(1000);     }     /*      * 交换次数最小也是1次，最大也是(n^2-n)/2次      */ //   ary=new int[]{10,9,8,7,6,5,4,3,2,1}; //测试交换次数 //   ary=new int[]{1,2,3,4,5,6,7,8,10,9}; //测试交换次数     System.out.println("-------排序前------");     for (int j = 0; j < ary.length; j++) {       System.out.print(ary[j] + " ");     }          orderAsc1(ary); //   orderAsc2(ary);          //降序，只需要把判断大小于 置换一下        }      static void orderAsc1(int[] ary) {     int compareCount = 0;//比较次数     int changeCount = 0;//交换次数     int len = ary.length;     int left = 0, right = len -1, tl, tr;     while (left < right) {//外层固定循环次数       tl = left + 1;       tr = right - 1;       for (int k = left; k < right; k++) {//内层从多到少递减比较次数, 从左向右         if (ary[k] > ary[k + 1]) {//前大于后， 置换           ary[k] = ary[k + 1] + (ary[k + 1] = ary[k]) * 0;//一步交换           changeCount++;           tr = k; //一轮中最后一比较的时候，将k所在索引赋给tr, tr表示以后比较的结束索引值, 从左向右比后，k表示左边的索引         }          compareCount++;       }       right = tr;       for (int k = right; k > left; k--) {//内层从多到少递减比较次数, 从右向左         if (ary[k] < ary[k - 1]) {//后小于前 置换           ary[k] = ary[k - 1] + (ary[k - 1] = ary[k]) * 0;//一步交换           changeCount++;           tl = k; //一轮中最后一比较的时候，将k所在索引赋给tl, tl表示以后比较的开始索引值, 从向右向左比后，k表示右边的索引         }          compareCount++;       }       left = tl;     }     System.out.println("/n-----orderAsc1升序排序后------比较次数：" + compareCount + ", 交换次数：" + changeCount);     for (int j = 0; j < len; j++) {       System.out.print(ary[j] + " ");     }   }      //跟orderAsc1的思路没有区别   static void orderAsc2(int[] ary) {     int compareCount = 0;//比较次数     int changeCount = 0;//交换次数     int len = ary.length;     int l = 0, r = len -1, tl, tr;     for (; l < r; ) {//外层固定循环次数       tl = l + 1;       tr = r - 1;       /*        * 从左向右比，将大的移到后面        */       for (int k = l; k < r; k++) {         if (ary[k] > ary[k + 1]) {           int temp = ary[k] + ary[k + 1];           ary[k + 1] = temp - ary[k + 1];           ary[k] = temp - ary[k + 1];           changeCount++;           tr = k;         }         compareCount++;       }       r = tr;       /*        * 从右向左比，将小的移到前面        */       for (int k = r; k > l; k--) {         if (ary[k] < ary[k - 1]) {           int temp = ary[k] + ary[k - 1];           ary[k - 1] = temp - ary[k - 1];           ary[k] = temp - ary[k - 1];           changeCount++;           tl = k;         }         compareCount++;       }       l = tl;     }     System.out.println("/n-----orderAsc2升序排序后------比较次数：" + compareCount + ", 交换次数：" + changeCount);     for (int j = 0; j < len; j++) {       System.out.print(ary[j] + " ");     }   } } 

-------排序前------ 783 173 53 955 697 839 201 899 680 677  -----orderAsc1升序排序后------比较次数：34, 交换次数：22 53 173 201 677 680 697 783 839 899 955