2.txt

Add Two Numbers

Given two linked lists we have to generate a single linked list which is the sum of both the linked lists

We can create a dummy linked list and add both numbers from the both of the linked lists and stores that in dummy linked list.
Use a carry to store if there is carry or not.

ListNode* addTwoNumbers(ListNode* l1, ListNode* l2) {
    ListNode *res=new ListNode(0,NULL);
    ListNode *temp=res;
    int carry=0,sum=0;
    while(l1 || l2){
        sum=(l1==NULL?0:l1->val) + (l2==NULL?0:l2->val) + carry;
        temp->next=new ListNode(sum%10);
        carry=sum/10;
        temp=temp->next;
        l1=l1?l1->next:NULL;
        l2=l2?l2->next:NULL;
    }
    if(carry){
        temp->next=new ListNode(carry,NULL);
    }
    return res->next;
}