15 February, 2026

Sunday grind. Not very productive because half of the day went into random chores
Today I:

• Solved the LeetCode POTD
• Learned linked lists
• Solved 3 additional linked list problems on LeetCode
• Attended a live class on System program, Token program and Solana CLI, etc

Not gonna lie, I felt a bit overwhelmed with all the jargon and how everything works. I thought I’d be able to write about what I learned today, but I don’t feel like I’ve built a solid understanding yet.

So I’ll revise it, experiment with it, and explain it properly later once things are clearer.

What I learned? (DSA)

Linked List

github-repo

It is a linear, non contiguous data structure, it has nodes, and each node contains data and a pointer to the next node. There is a pointer called head that points to the first NODE, and tail that points to NULL in case of a singly linked list.

Defining Node: It has data and a Node pointer.

// Node Class
class Node{
    public:
        int data;
        Node* next;
 
        Node(int val){
            data = val;
            next = NULL;
        }
     
};

Defining List: It has the head and tail pointers, with additional methods like push_front, push_back, pop_front, pop_back. I have only implemented push_front and push_back for now, will implement the rest two tomorrow. I have also implemented the print list method to print the linked list.

// List Class
class List{
    Node* head;
    Node* tail;
 
    public:
        List(){
            head = tail = NULL;
        }
        
        void push_front(int val){
            Node* newNode = new Node(val);
            if(head == NULL){
                head = tail = newNode;
                return;
            }else{
                newNode->next = head;
                head = newNode;
            }
        }
 
        void push_back(int val){
            Node* newNode = new Node(val);
            if(head == NULL){
                head = tail = newNode;
            }else{
                tail->next = newNode;
                tail = newNode;
            }
        }
 
        // Print Linked List
        void printLinkedList(){
            Node* temp = head;
            while (temp != NULL){
                cout << temp->data << "->";
                temp = temp->next; 
            }
            cout << "NULL" << endl;
        }
};
 

That's it for today! Will see you in the next one.
Keep learning and growing.