Algorithm

Backtracking builds solutions by exploring all options and undoing choices when needed. To print numbers from n down to 1 using backtracking, the function recursively calls itself with the previous number until it goes below 1. After reaching the base case, it prints the numbers while returning from the recursion. This way, numbers are printed in ascending order because the print happens after the recursive call during backtracking. The main difference from forward recursion is that printing occurs on the way back, not before the recursive call.

Code

#include <bits/stdc++.h>
using namespace std;

class Solution {
public:
    // Recursive function to print numbers from current down to 1 using backtracking
    void printNumbers(int current) {
        // Base case: if current is less than 1, stop recursion
        if (current < 1)
            return;

        // Recursive call with previous number
        printNumbers(current - 1);

        // Print current number during backtracking
        cout << current << " ";
    }
};

int main() {
    Solution sol;
    int n = 10;

    sol.printNumbers(n);
    cout << "\n";

    return 0;
}