reverse linked list

rev_linked_list.cpp

//
// Recursively change each node of the linked list such that next
// is the last node seen during a linear scan of the linked list.
//
class Solution {
public:
    using fun = function<ListNode*(ListNode*, ListNode*)>;
    ListNode* reverseList(ListNode* head) {
        fun go = [&](auto node, auto last) {
            auto next = node->next;
            node->next = last;
            if (!next)
                return node;
            return go(next, node);
        };
        return head ? go(head, nullptr) : nullptr;
    }
};