Print N to 1 without Loop

Summary

This problem requires you to print numbers from N to 1, but without using a loop. The key concept involved is recursion, which allows us to break down the problem into smaller sub-problems and solve them in a similar way.

Detailed Explanation

To solve this problem, we will use recursion to print the numbers from N to 1. Here's how it works:

We start by printing the number N.
Then, we call the same function recursively with N-1 as the input.
This process continues until we reach 1, at which point we stop calling the function.

Here's a step-by-step breakdown of the solution:

PrintN(int n) {
    if (n > 0) {
        PrintN(n - 1);
        System.out.println(n);
    }
}

We start by printing the number N. Then, we call the same function recursively with N-1 as the input. This process continues until we reach 1, at which point we stop calling the function.

The time complexity of this solution is O(N), where N is the input number. The space complexity is O(1) because we only use a constant amount of space to store the recursive function call.

Optimized Solutions

Java

public class PrintN { public static void printN(int n) { if (n > 0) { System.out.println(n); printN(n - 1); } } public static void main(String[] args) { printN(5); // prints 5, 4, 3, 2, 1 } }