The ultimate guide to recursion interviews. Developed by FAANG engineers, practice with real-world C++ problems, interactive code playgrounds, and get interview-ready in just a few hours.

If you’ve ever struggled with solving coding problems using recursion, or if you’ve just got an interview coming up and want to brush up on your knowledge, you’ll definitely find this course helpful.
 
You’ll start with the basics of what recursion is and why it’s important before diving into what it looks like in practice. You’ll see how recursion can help you solve a variety of different math, string, and data structure problems, using interactive code playgrounds you can execute directly in your browser. You’ll have access to detailed explanations and visualizations for each problem to help you along the way.  
 
By the time you’re done, you’ll be able to use what you’ve learned to solve complex real-world problems, and even advance more easily through your interviews at top tech companies.

Recursion for Coding Interviews in C++

 ```C++
 if (head==NULL)
    {
        return;
    }
```

 ```C++
 if (head->next==NULL)
    {
        return;
    }
```

Assume that you have a linked list with five nodes. The task is to traverse the linked list recursively. 
``` C++
void printListRecursively(Node* head)
{
 //base case
 //recursive case
 cout << head->data <<endl;
 printListRecursively(head->next);
}
````
What would be the base case of the above code?

Assume that you have a linked list with five nodes. The task is to traverse the linked list recursively.
<pre><code class="language-C++">void printListRecursively(Node* head)
{
 //base case
 //recursive case
 cout &lt;&lt; head-&gt;data &lt;&lt;endl;
 printListRecursively(head-&gt;next);
}
</code></pre>
What would be the base case of the above code?

Assume that you have a graph with four nodes. The graphs have edges as follows: 
{ [ 0,1 ], [ 0,2 ] ,[ 1,4 ], [ 1,3 ], [ 2, 4 ] } 
The function below prints the nodes and vertices that each vertex is connected to. 
What would be the base case of the above code?


``` C++
void connected(int v, vector<int>visited)
{
 //base case
 //recursive case
 	connected(v+1,visited);
 
 
}
````
What would be the base case of the above code?

Assume that you have a graph with four nodes. The graphs have edges as follows:
{ [ 0,1 ], [ 0,2 ] ,[ 1,4 ], [ 1,3 ], [ 2, 4 ] }
The function below prints the nodes and vertices that each vertex is connected to.
What would be the base case of the above code?
<pre><code class="language-C++">void connected(int v, vector&lt;int&gt;visited)
{
 //base case
 //recursive case
 	connected(v+1,visited);
 
 
}
</code></pre>
What would be the base case of the above code?

```c++
if (root != NULL) 
 
  {
    root = newTreeNode(data);
    return;
  }
```

```c++
if (root == NULL) 
  {
    root = newTreeNode(data);
    return;
  }
```

```c++
if (root == NULL) 
  {
    return;
  	root = newTreeNode(data);
  }
```

See the code for BST implement ation below:

```c++
struct TreeNode
{
 int value;
 TreeNode *left; 
 TreeNode *right;
};

TreeNode* newTreeNode(int data)
{
 TreeNode* temp = new TreeNode;
 temp->value = data;
 temp->left = NULL;
 temp->right = NULL;

 return temp;
}

void insert(TreeNode* &root, int data)
{
 // base case
 
 if (data<root->value)
 {
 insert(root->left,data); 
 }
 else
 {	
 insert(root->right, data); 
 }
}
```
What is the base case for the `insert` function?

See the code for BST implement ation below:
<pre><code class="language-c++">struct TreeNode
{
 int value;
 TreeNode *left; 
 TreeNode *right;
};

TreeNode* newTreeNode(int data)
{
 TreeNode* temp = new TreeNode;
 temp-&gt;value = data;
 temp-&gt;left = NULL;
 temp-&gt;right = NULL;

 return temp;
}

void insert(TreeNode* &amp;root, int data)
{
 // base case
 
 if (data&lt;root-&gt;value)
 {
 insert(root-&gt;left,data); 
 }
 else
 {	
 insert(root-&gt;right, data); 
 }
}
</code></pre>
What is the base case for the <code>insert</code> function?

Solve this Quiz!

Solve this Quiz!

This lesson will test your knowledge on how to solve linked list, trees ,and graph problems using recursion.

Recursion Fundamentals

Recursion with Numbers

Recursion With Strings

Recursion With Arrays

Recursion with Data Structures

Quick Quiz on Recursion with Data Structures!