冒泡排序优化算法

import java.util.Arrays;
public class Arithmetic {
    public static void main(String[] args) {
        int[] arr = {3, 1, 6 ,2, 9, 0, 7, 4, 8, 5 };
        System.out.println(Arrays.toString(arr));
        bubbleSort(arr);
        System.out.println(Arrays.toString(arr));
    }
    public static void bubbleSort(int[] arr){
        boolean flag = true;
        for (int i = 0; i < arr.length; i++) {
            for (int j = 0; j < arr.length - 1 - i; j++) {
                if (arr[j] > arr[j + 1]){
                    int temp = arr[j];
                    arr[j] =  arr[j + 1];
                    arr[j + 1] = temp;
                    flag = false;
                }
                System.out.println("第" + i + "躺第" + j + "次" + Arrays.toString(arr));
            }
            if(flag){
                System.out.println("冒泡优化，结束排序");
                break;
            }else{
                flag = true;
            }
        }
    }
}

二分法查找算法

import java.util.Arrays;
public class Query {
    public static void main(String[] args) {
        int[] arr = {30, 20, 50, 10, 80, 9, 7, 12, 100, 40, 8};
        int index = findIndex(30, arr);
        System.out.println(index);
    }
    public static int findIndex(int x, int[] arr) {
        Arithmetic.bubbleSort(arr);
        System.out.println(Arrays.toString(arr));
        int start = 0;
        int end = arr.length - 1;
        while(start <= end){
            int mid = (start + end)/ 2;
            if(arr[mid] == x){
                return mid;
            }
            if(arr[mid] > x){
                end = mid - 1;
            }
            if(arr[mid] < x){
                start = mid + 1;
            }
        }
        return -1;
    }
}