Added Recursion Problems

Author: bakisama

content/cp/gfg/Factorials Less than or Equal to n.md

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+---
+created: 2025-12-17
+modified:
+completed: true
+platform: gfg
+problem-id:
+link: https://www.geeksforgeeks.org/problems/find-all-factorial-numbers-less-than-or-equal-to-n3548/0
+difficulty: Easy
+tags:
+  - gfg
+---
+# Factorials Less than or Equal to n | Practice | GeeksforGeeks
+
+## Question
+### Factorials Less than or Equal to n
+
+A number **n** is called a factorial number if it is the factorial of a positive integer. For example, the first few factorial numbers are 1, 2, 6, 24, 120,  
+Given a number **n**, the task is to return the list/vector of the factorial numbers smaller than or equal to n.
+
+**Examples:**
+
+```
+Input: n = 3
+Output: 1 2
+Explanation: The first factorial number is 1 which is less than equal to n. The second number is 2 which is less than equal to n,but the third factorial number is 6 which is greater than n. So we print only 1 and 2.
+```
+```
+Input: n = 6
+Output: 1 2 6
+Explanation: The first three factorial numbers are less than equal to n but the fourth factorial number 24 is greater than n. So we print only first three factorial numbers.
+```
+
+**Constraints:**  
+1<=n<=10 <sup>18</sup>
+---
+
+## Solution
+
+### Intuition
+
+### Approach
+
+### Complexity
+- Time:
+- Space:
+
+### Code
+---
+[!]
+```cpp
+// User function Template for C++
+class Solution {
+  public:
+    vector<long long> factorialNumbers(long long n) {
+        vector<long long> vec;
+        if (n<=1) return vec;
+        for(int i = 1,temp=1;i<=n;){
+            cout<<i<<" ";
+            i=i*(++temp);
+        }
+        
+    }
+};
+```
+
+### Optimal Code
+---
+[!]
+```cpp
+vector<long long> result;
+
+long long fact = 1;
+long long k = 1;
+
+while (fact <= n) {
+  result.push_back(fact);
+  k++;
+  if (fact > n / k) break;  // prevent overflow
+  fact *= k;
+}
+
+return result;
+```
+

content/cp/gfg/Print 1 To N Without Loop.md

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+---
+created: 2025-12-17
+modified:
+completed: true
+platform: gfg
+problem-id:
+link: https://www.geeksforgeeks.org/problems/print-1-to-n-without-using-loops-1587115620/1
+difficulty: Basic
+tags:
+---
+# Print 1 To N Without Loop | Practice | GeeksforGeeks
+
+## Question
+### Print 1 To N Without Loop
+
+You are given an integer **n**. You have  to print all numbers from **1** to **n**.  
+**Note**: You must use **recursion** only,andprint all numbers from **1** to **n** in a single line, separated by spaces.
+
+**Examples:  
+**
+
+```
+Input: n = 10
+Output: 1 2 3 4 5 6 7 8 9 10
+```
+```
+Input: n = 5
+Output: 1 2 3 4 5
+```
+```
+Input: n = 1
+Output: 1
+```
+
+**Constraints:**  
+1 ≤ n ≤ 10 <sup>3</sup>
+
+If you are facing any issue on this page. Please let us know.
+
+---
+
+## Solution
+
+### Intuition
+
+### Approach
+
+### Complexity
+- Time:
+- Space:
+
+### Code
+---
+[!]
+```cpp
+class Solution {
+  public:
+    void printNos(int n) {
+        if(n==0) return;
+        printNos(n-1);
+        cout<<n<<" ";
+    }
+};
+```
+
+### Optimal Code
+---
+[!]
+```cpp
+
+```
+