题解 | #链表相加(二)#

/**
 * struct ListNode {
 *	int val;
 *	struct ListNode *next;
 *	ListNode(int x) : val(x), next(nullptr) {}
 * };
 */
#include <memory>
#include <utility>

class Solution {
public:
    /**
     * 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
     *
     * 
     * @param head1 ListNode类 
     * @param head2 ListNode类 
     * @return ListNode类
     */
    ListNode* addInList(ListNode* head1, ListNode* head2) {
        auto Rev = [](ListNode* head) {
            auto prev = head;
            auto cur = prev->next;
            if(not cur) return prev;
            prev->next = nullptr;
            while(cur) {
                auto t = cur->next;
                cur->next = prev;
                prev = cur;
                cur = t;
            }
            return prev;
        };
        auto rh1 = Rev(head1);
        auto root = rh1;
        auto rh2 = Rev(head2);
        while(rh2) {
            rh1->val += rh2->val;
            rh2 = rh2->next;

            if(not rh1->next) break;
            rh1 = rh1->next;
        }
        if(rh2) {
            rh1->next = rh2;
        }

        // 进位处理
        for(auto cur = root; cur; cur = cur->next) {
            auto& v = cur->val;
            if(v >= 10) {
                if(not cur->next) {
                    mem.emplace_back(std::make_unique<ListNode>(0));
                    cur->next = mem.back().get();
                }
                cur->next->val += v / 10;
                v %= 10;
            }
        }

        return Rev(root);
    }

    std::vector<std::unique_ptr<ListNode>> mem;
};