question:

//Given a non-negative number represented as an array of digits, plus one to the number.
//
//The digits are stored such that the most significant digit is at the head of the list.

answer:

public class pulsOne {
    
    public static int[] plusOne(int[] array){
        int one =1;
        int sum =0;
        for (int i =array.length-1;i>=0;i--){
            sum = one + array[i];
            one = sum/10;
            array[i] = sum%10;
        }
        if(one==0){
            return array;
        }
        int[] plusresult = new int[array.length+1];
        plusresult[0] =1;
        for(int i=0;i<array.length;i++){
            plusresult[i+1] = array[i];
        }
        return plusresult;
    }

    public static void main(String[] args) {
        int[] array1 ={8,7};
        
        System.out.println(Arrays.toString(plusOne(array1)));
        // TODO Auto-generated method stub

    }

之前蠢了，打印数组用Arrays.toString()方便很多
直接在System.out.println()打印数组，出来只是数组的内存地址
继续学习