java一些封装好的常用算法

1.简单排序Collections.sort()：

 //简单排序
 List<String> staff= new LinkedList<>();
         staff.add("aty");
         staff.add("world");
         staff.add("hello");
         Collections.sort(staff);//升序
         staff.sort(Comparator.reverseOrder());//降序
         System.out.println(staff.toString());

2.混排Collections.shuffle():

 //混排
         List<Integer> numbers = new ArrayList<>();
         for (int i = 0; i < 49; i++) {
             numbers.add(i);
         }
         Collections.shuffle(numbers);
         List<Integer> combining = numbers.subList(0, 6);
         Collections.sort(combining);
         System.out.println(combining);

3.二分Collections.binarySearch():

 //二分
         List<Integer> list = new ArrayList<>();
         for (int i = 0; i < 10; i++) {
             list.add(i);
         }
         System.out.println(list.toString());
     System.out.println(Collections.binarySearch(list, 8));

4.一些简单的算法实现：

 //简单算法实现
         ArrayList<Integer> numbers = new ArrayList<>();
         for (int i = 0; i < 49; i++) {
             numbers.add(i);
         }
         System.out.println(Collections.min(numbers));//最小
          System.out.println(Collections.max(numbers));//最大

          ArrayList<Integer> numbers2 = new ArrayList<>();
          numbers2 = (ArrayList<Integer>) numbers.clone();
          System.out.println(numbers.toString()); //复制

          Collections.fill(numbers, 1000);
          System.out.println(numbers.toString());//所有值换成1000

          Collections.addAll(numbers, 300,800,100);
          System.out.println(numbers.toString());//添加所有值进去

          Collections.replaceAll(numbers, 3, 900);//将所有3提传成900

          ArrayList<Integer> sublist =new ArrayList<>();
          for(int i=0;i<4;i++){
              sublist.add(i);
          }
       System.out.println(Collections.indexOfSubList(numbers,sublist));

          Collections.swap(numbers, 2, 3);
          System.out.println(numbers.toString());//交换俩元素位置

          Collections.reverse(numbers);
          System.out.println(numbers);//倒置列表元素

          Collections.rotate(numbers, 2);
          System.out.println(numbers.toString());//旋转列表元素

 //         Collections.frequency(c, o);//返回c中与o相同的元素个数
 //         Collections.disjoint(c1, c2);//如果两个集合没有相同的元素，则返回true
          

5.栈：

 //栈
         Stack<Integer> stack = new Stack<>();
         stack.push(5);//将5压入栈并返回5
         stack.pop();//弹出并返回栈顶的元素，栈为空不能调用
         stack.peek();//返回栈顶元素，但不弹出