Basic usage of analog Addition & structure

leetcode Addition of two numbers

/** * Definition for singly-linked list. * struct ListNode { * int val; * ListNode *next; * ListNode() : val(0), next(nullptr) {} * ListNode(int x) : val(x), next(nullptr) {} * ListNode(int x, ListNode *next) : val(x), next(next) {} * }; */
class Solution {
    
public:
    ListNode* addTwoNumbers(ListNode* l1, ListNode* l2) {
    
        struct ListNode* dummy=new ListNode(-1);
        struct ListNode* cur=dummy;
        // perhaps 
      	auto dummy=new ListNode(-1),cur=dummy;
        
        int t=0;
        while(l1 || l2 || t)
        {
    
            if(l1) t+=l1->val,l1=l1->next;
            if(l2) t+=l2->val,l2=l2->next;
            cur->next=new ListNode(t%10);
            cur=cur->next;
            t/=10;
        }

        return dummy->next;
    }
};