Reverse the Linked List using iterative method, Explain me using step by step like a beginner

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Welcome to linked list reversal! A linked list is a data structure where each node contains data and a pointer to the next node. Our goal is to reverse the direction of all pointers so the list flows backward. Let's see what this looks like visually. Now let's set up our three essential pointers. First, we initialize current to point at the head of the list. Second, we set previous to null since there's no node before the first one. Third, we set next_node to point to the second node to save our path forward. These three pointers work together to help us navigate and modify the list safely. Let's walk through the first iteration step by step. First, we save the next node by setting next_node to current.next, which points to node 2. Second, we reverse the current node's pointer by setting current.next to previous, making node 1 point to null. Third, we move previous to the current node. Finally, we move current to the saved next_node. After this iteration, node 1 now points backward to null instead of forward to node 2. We continue this process for all remaining nodes. In iteration 2, we reverse node 2 to point to node 1. In iteration 3, we reverse node 3 to point to node 2. The loop continues until current becomes null, meaning we've processed all nodes. At this point, previous points to what was originally the last node, which is now our new head. We return previous as the head of our completely reversed linked list. The reversal is now complete! To summarize what we've learned: We use three pointers to safely track our position during the reversal process. Each iteration reverses exactly one node's pointer direction. The algorithm runs in linear time with constant space complexity, making it very efficient. This iterative approach is memory-friendly and represents a fundamental technique used in many advanced linked list problems.