JAVA数组练习代码

一维数组的有序插入

思路

代码

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import java.util.Scanner;

/**
 * @author LittleBear
 * @date 2024-02-02 - 16:57
 */
public class seqInsertion {
    public static void main(String[] args) {
        System.out.println("please input your num:");
        Scanner myScanner = new Scanner(System.in);
        int insertNum = myScanner.nextInt();

        int len = 10;
        int arr[] = new int[len];
        for (int i = 0; i < len; i++) {
            arr[i] = (int)(Math.random()*100+1);
//            System.out.println(arr[i]);
        }
        for (int i = 0; i < arr.length-1; i++) {
            for (int j = 0; j < arr.length-1-i; j++) {
                if(arr[j] > arr[j+1]){
                    int tmp = arr[j];
                    arr[j] = arr[j+1];
                    arr[j+1] = tmp;
                }
            }
        }
       

        int index = -1;
        for (int i = 0; i < arr.length; i++) {
            if (insertNum <= arr[i]){
                index = i;
                break;
            }
        }
        if (index == -1){
            index = arr.length;
        }
        int[] newArr = new int[arr.length+1];
        for (int i = 0, j = 0; i < newArr.length; i++) {
            if (i != index){
                newArr[i] = arr[j];
                j++;
            }
            else{
                newArr[i] = insertNum;
            }
        }
        arr = newArr;

        for (int i = 0; i < arr.length; i++) {
            System.out.print(arr[i] + " " );
        }

    }
}

杨辉三角（二维数组）

思路

代码

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/**
 * @author LittleBear
 * @date 2024-02-02 - 14:50
 */
public class yanghui {
    public static void main(String[] args) {
        int[][] yang = new int[12][];
        for (int i = 0; i < yang.length; i++) {
            yang[i] = new int[i+1];//给每一个一维数组开辟空间

            for (int j = 0; j < yang[i].length; j++) {
                if(j == 0 || j== yang[i].length - 1){//给每一行的第一个和最后一个元素赋值
                    yang[i][j] = 1;
                }
                else{//中间元素赋值
                    yang[i][j] = yang[i-1][j-1] + yang[i-1][j];
                }
            }
        }

        for (int i = 0; i < yang.length; i++) {
            for (int j = 0; j < yang[i].length; j++) {
                System.out.print(yang[i][j] + "\t");
            }
            System.out.println();
        }
    }
}

冒泡排序（一维数组）

代码

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/**
 * @author LittleBear
 * @date 2024-02-02 - 14:49
 */
public class sort {
    public static void main(String[] args) {
        int len = 10;
        int[] arr = new int[10];
        for (int i = 0; i < len; i++) {
            arr[i] = (int)(Math.random()*100)+1;
//            System.out.println(arr[i]);
        }

        for (int i = 0; i < len -1; i++) {
            for (int j = 0; j < len - i -1; j++) {
                if(arr[j] > arr[j+1]){
                    int tmp = arr[j];
                    arr[j] = arr[j+1];
                    arr[j+1] = tmp;
                }
            }
        }

        for (int i = 0; i < len; i++) {
            System.out.print(arr[i] + " ");
        }
    }
}