2.Add Two Numbers (List)
You are given two linked lists representing two non-negative numbers. The digits are stored in reverse order and each of their nodes contain a single digit. Add the two numbers and return it as a linked list.
Input: (2 -> 4 -> 3) + (5 -> 6 -> 4)
Output: 7 -> 0 -> 8
/** * Definition for singly-linked list. * struct ListNode { * int val; * ListNode *next; * ListNode(int x) : val(x), next(NULL) {} * }; */ class Solution { public: ListNode* addTwoNumbers(ListNode* l1, ListNode* l2) { int sum = l1->val + l2->val; int carry = sum/10; ListNode* root = new ListNode(sum%10); ListNode* current = root; l1 = l1->next; l2 = l2->next; while(l1 && l2){ sum = l1->val + l2->val + carry; carry = sum/10; current->next = new ListNode(sum%10); current = current->next; l1 = l1->next; l2 = l2->next; } while(l1){ sum = l1->val+ carry; carry = sum/10; current->next = new ListNode(sum%10); current = current->next; l1 = l1->next; } while(l2){ sum = l2->val+ carry; carry = sum/10; current->next = new ListNode(sum%10); current = current->next; l2 = l2->next; } if(carry){ current->next = new ListNode(carry); } return root; } };