#include <cstdio>
#include <iostream>

using namespace std;

void printNumList(int level);
void printNumber(int index, char *seq, const int maxLevel);

int main()
{
    while (1){
        printf("Press 0 to exit.\n");
        printf("Press 1 to do the nonrecursive mission.\n");
        printf("Press 2 to do the recursive mission.\n");
        int Num;
        scanf("%d", &Num);

        if (Num == 0) { //exit
            break;
        }

        else if (Num == 1){ //nonrecursive
        }
        else if (Num == 2){ //recursive
            printf("Please enter a number between 1 to 9: ");
            int InputNum;
            cin >> InputNum;

            if(InputNum > 9 || InputNum < 1) {
                printf("Invalid number, please try again.\n");
            }

            // Do the process
            printNumList(InputNum);
        }
    }

    return 0;
}

void printNumList(int level)
{
    // create output string
    char *seq = new char[level+1];
    seq[level] = '\0';

    //start recursion
    printNumber(0, seq, level-1);
}

void printNumber(int index, char *seq, const int maxLevel)
{
    // recursion stop point
    if (index > maxLevel)
        return;

    for (char c = '0'; c <= '9'; ++c){

        // check repeat
        bool repeat = false;
        for (int j = 0; seq[j] != '\0'; ++j){
            if ( c == seq[j]){
                repeat = true;
                break;
            }
        }
        if (repeat)
            continue;

        // assign number
        seq[index] = c;
        printNumber(index+1, seq, maxLevel);

        // output
        if (index == maxLevel){
            cout << seq << endl;
        }

        // clear number in seqence
        seq[index] = '\0';
    }
}