035Reverse Linked List

def reverseList(head):
    prev, curr = None, head
    while curr:
        next_node = curr.next  # save next
        curr.next = prev       # reverse pointer
        prev = curr            # advance prev
        curr = next_node       # advance curr
    return prev

public ListNode reverseList(ListNode head) {
    ListNode prev = null, curr = head;
    while (curr != null) {
        ListNode next = curr.next;
        curr.next = prev;
        prev = curr;
        curr = next;
    }
    return prev;
}

fun reverseList(head: ListNode?): ListNode? {
    var prev: ListNode? = null
    var curr = head
    while (curr != null) {
        val next = curr.next
        curr.next = prev
        prev = curr
        curr = next
    }
    return prev
}

ListNode* reverseList(ListNode* head) {
    ListNode* prev = nullptr;
    ListNode* curr = head;
    while (curr) {
        ListNode* next = curr->next;
        curr->next = prev;
        prev = curr;
        curr = next;
    }
    return prev;
}