Java 递归码的基例打印格式良好的数字

我在网上发现了一个问题：给定输入大小，打印出该大小的所有格式正确的数字。

示例：大小=3 数字：123、234、125等条件，假设数字是abc然后a 我正试图为此编写一个递归代码，由于我对递归的理解很差，所以我无法理解基本情况，或者如何从递归中走出来。我有一个想法：

我从给定大小的最小格式良好的数字开始（只需用循环的

填充数组即可）。假设size=3，我从
123
开始。然后我继续，直到
arr[0]==（10-size））
因为这是给定大小的
arr[0]
的最大值，是一个格式良好的数字
我的函数是
printNumber（int-arr[]，int-size）

但我不确定这是否有效。需要一些指向正确方向的指针

public void findNumbers(int arr[], int size, int pos)
    {
        if(arr[0] == (10 - size))
            return;
        if(arr[pos] == (10 - size + pos))
        {
            pos--;
            findNumbers(arr,size,pos);
        }
        System.out.println(Arrays.toString(arr));
        arr[pos] = arr[pos] + 1;
        findNumbers(arr,size,pos);
    }

    public static void main(String[] args)
    {
        int size = 3;
        int pos = size-1;
        int arr[] = new int[size];
        for(int i = 0; i<size; i++)
        {
            arr[i] = i+1;
        }
        //System.out.println(Arrays.toString(arr));
        WellFormed obj = new WellFormed();
        obj.findNumbers(arr, size, pos);
    }

public void findNumbers（int arr[]，int size，int pos）
{
如果（arr[0]==（10-大小））
返回；
如果（arr[pos]==（10-尺寸+pos））
{
pos--；
FindNumber（arr、尺寸、位置）；
}
System.out.println（Arrays.toString（arr））；
arr[pos]=arr[pos]+1；
FindNumber（arr、尺寸、位置）；
}
公共静态void main（字符串[]args）
{
int size=3；
int pos=尺寸-1；
int arr[]=新的int[size]；
对于（inti=0；i我认为你对这个问题的理解比没有概念要复杂得多，因为看到了你清晰的描述。所以，这一次我回答了这样典型的“家庭作业”

public void giveWellFormedNumbers（int-inputSize）{
int[]位=新的int[intputSize]；
给定的数字（数字，0，1）；
}
/**
*@param fromIndex完成的位数，继续的起始索引。
*/
私有数字（int[]位，int fromIndex，int fromDigitValue）{
if（fromIndex>=位数.length）{
System.out.println（数组.toString（数字））；
返回；
}
//在数字[fromIndex]处自己做一个数字：
int maxDigit=10-digits.length；//必须执行的最大数字是什么？
对于（int digitValue=fromDigitValue；digitValue它必须是Java吗？这里是Haskell五行代码中的一个解决方案。我喜欢这个（以及其他Haskell代码）的地方是它基本上读起来像是问题的定义

wellFormed::Int->[a]->[[a]]
wellFormed _ [] = []
wellFormed 1 xs = map (\x -> [x]) xs
wellFormed n (x:xs) = helper n x xs ++ wellFormed n xs
  where helper n init rest = map ((:) init) (wellFormed (n - 1) rest)

> wellFormed 3 "123456789"
["123","124","125","126","127","128","129","134","135","136","137","138","139","145","146","147","148","149","156","157","158","159","167","168","169","178","179","189","234","235","236","237","238","239","245","246","247","248","249","256","257","258","259","267","268","269","278","279","289","345","346","347","348","349","356","357","358","359","367","368","369","378","379","389","456","457","458","459","467","468","469","478","479","489","567","568","569","578","579","589","678","679","689","789"]

为什么不试试看，当你卡住的时候，把你的代码贴在这里？@DNA:我已经展示了我写的代码。问题是它在到达
789
后并没有停止。我不知道如何
破解。
import java.util.Arrays;

public class WellFormed {

    public static int maxDigit;

    public void findNumbers(int[] digits, int start, int currPos) {
        if (currPos >= digits.length) {
            System.out.println(Arrays.toString(digits));
            return;
        }

        int maxDigitInCurrPos = maxDigit - digits.length + currPos + 1;
        for (int i = start; i <= maxDigitInCurrPos; i++) {
            digits[currPos] = i;
            findNumbers(digits, i+1, currPos + 1);
        }
    }

    public static void main(String[] args)
    {   
        WellFormed obj = new WellFormed();
        maxDigit = 5;
        int inputSize = 3;
        int[] digits = new int[inputSize];
        obj.findNumbers(digits, 1, 0);
    }
}

For inputSize = 3 and maxDigit = 5, output is:

[1, 2, 3]
[1, 2, 4]
[1, 2, 5]
[1, 3, 4]
[1, 3, 5]
[1, 4, 5]
[2, 3, 4]
[2, 3, 5]
[2, 4, 5]
[3, 4, 5]

wellFormed::Int->[a]->[[a]]
wellFormed _ [] = []
wellFormed 1 xs = map (\x -> [x]) xs
wellFormed n (x:xs) = helper n x xs ++ wellFormed n xs
  where helper n init rest = map ((:) init) (wellFormed (n - 1) rest)

> wellFormed 3 "123456789"
["123","124","125","126","127","128","129","134","135","136","137","138","139","145","146","147","148","149","156","157","158","159","167","168","169","178","179","189","234","235","236","237","238","239","245","246","247","248","249","256","257","258","259","267","268","269","278","279","289","345","346","347","348","349","356","357","358","359","367","368","369","378","379","389","456","457","458","459","467","468","469","478","479","489","567","568","569","578","579","589","678","679","689","789"]