常见排序算法Java版（待续）

1. 冒泡排序O(n^2)

   public class Main {
       public static void main(String[] args) {
           Random random = new Random();
           int[] nums = new int[]{random.nextInt(100), random.nextInt(100), random.nextInt(100), random.nextInt(100), random.nextInt(100), random.nextInt(100)};
           for (int i = nums.length - 1; i >= 0; i--) {
               for (int j = 0; j < i; j++) {
                   if (nums[j] > nums[j + 1]) {
                       int temp = nums[j];
                       nums[j] = nums[j + 1];
                       nums[j + 1] = temp;
                   }
               }
           }
           for (int num : nums) {
               System.out.print(num + " ");
           }
       }
   }

   

2. 选择排序O(n^2),

   public class Main {
       public static void main(String[] args) {
           Random random = new Random();
           int[] nums = new int[]{random.nextInt(100), random.nextInt(100), random.nextInt(100), random.nextInt(100), random.nextInt(100), random.nextInt(100)};
           int index;
           for (int i = 0; i < nums.length; i++) {
               index = i;//每一轮记录最小值的索引
               for (int j = i + 1; j < nums.length; j++) {
                   if (nums[j] < nums[index]) {
                       index = j;
                   }
               }
               if (index != i) {
                   int temp = nums[i];
                   nums[i] = nums[index];
                   nums[index] = temp;
               }
           }
           for (int num : nums) {
               System.out.print(num + " ");
           }
       }
   }

   

3. 插入排序O(n^2)

   public class Main {
       public static void main(String[] args) {
           Random random = new Random();
           int[] nums = new int[]{random.nextInt(100), random.nextInt(100), random.nextInt(100), random.nextInt(100), random.nextInt(100), random.nextInt(100)};
           int index;
           for (int i = 1; i < nums.length; i++) {
               int rec = nums[i];
               index = i;
               for (int j = i - 1; j >= 0; j--) {
                   if (nums[j] > rec) {
                       nums[index] = nums[j];
                       index = j;
                   } else {
                       break;
                   }
               }
               nums[index] = rec;
           }
           for (int num : nums) {
               System.out.print(num + " ");
           }
       }
   }