Day06

冒泡排序

import java.util.Arrays;

public class 冒泡 {
    public static void main(String[] args) {
        int[] a = {1,5,6,3,2,5,8,5,2,6};
        int[] sort = sort(a);
        System.out.println(Arrays.toString(sort));
    }
    //冒泡排序
    //比较数组中两个数
    public static int[] sort(int[] array){
            int temp = 0;
            for (int i=0;i<array.length-1;i++){
                for (int j=0;j < array.length-1-i;j++){
                    if (array[j+1] < array[j]){
                        temp = array[j];
                        array[j] = array[j+1];
                        array[j+1]=temp;
                    }
                }
            }
    return array;
    }
}

稀疏数组

• 大部分都是0

  定义：把具有不同值的元素和行列记录在一个小规模数组中

  行	列	值（多少有效数字）

public class ShuZu {
    public static void main(String[] args) {
        //创建一个二维数组
        int[][] array1 = new int[11][11];
        array1[1][2] = 1;
        array1[2][3] = 2;
        System.out.println("输出原始数组：");
        for (int[] ints : array1) {
            for (int anInt : ints) {
                System.out.print(anInt+"\t");
            }
            System.out.println();
        }

        //转换为稀疏数组
        //获取有效值
        int sum = 0;
        for (int i = 0; i < 11; i++) {
            for (int j = 0; j < 11; j++) {
                if(array1[i][j]!=0){
                sum++;
                }
            }
        }
        System.out.println("有效值个数"+sum);
        //创建一个稀疏数组
        int[][] array2 = new int[sum+1][3];
        array2[0][0] = 11;
        array2[0][1] = 11;
        array2[0][2] = sum;
        //遍历二维数组，将非0放入稀疏数组
        int count = 0;
        for (int i = 0; i < array1.length; i++) {
            for (int j = 0; j < array1[i].length; j++) {
                if (array1[i][j]!=0){
                    count++;
                    array2[count][0] = i;
                    array2[count][1] = j;
                    array2[count][2] = array1[i][j];

                }
            }
        }
        System.out.println("输出稀疏数组：");
        for (int i = 0; i < array2.length; i++) {
            System.out.println(array2[i][0]+"\t"+array2[i][1]+"\t"+array2[i][2]+'\t');
        }

        //还原
        //读取稀疏数组
        int[][] array3 = new int[array2[0][0]][array2[0][1]];
        //还原值
        for (int i = 1; i < array2.length; i++) {
            array3[array2[i][0]][array2[i][1]] = array2[i][2];
        }
        //打印
        for (int[] ints : array1) {
            for (int anInt : ints) {
                System.out.print(anInt+"\t");
            }
            System.out.println();
        }

    }
}