LeetCode刷题系列之Add Two Numbers

Description

You are given two non-empty linked lists representing two non-negative integers. 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.

You may assume the two numbers do not contain any leading zero, except the number 0 itself.

Input: (2 -> 4 -> 3) + (5 -> 6 -> 4)
Output: 7 -> 0 -> 8

Solution

class Solution {
public:
 ListNode* addTwoNumbers(ListNode* l1, ListNode* l2) {
 ListNode *l1Head = l1;
 ListNode *l2Head = l2;

 ListNode *addedHead = NULL;

 ListNode *item = NULL;

 int l1Val = 0;
 int l2Val = 0;
 int sumVal = 0;
 bool bDeca = false;
 bool bQuitL1 = false;
 bool bQuitL2 = false;

 while (true) {
     if (l1Head) {
         l1Val = l1Head->val;

         l1Head = l1Head->next;
     } else {
         l1Val = 0;
         bQuitL1 = true;
     }

     if (l2Head) {
         l2Val = l2Head->val;

         l2Head = l2Head->next;
     } else {
         l2Val = 0;
         bQuitL2 = true;
     }

     if (bQuitL1 && bQuitL2 && !bDeca) {
         break;
     }

     if (bDeca) {
         sumVal += 1;
         // reset bDeca
         bDeca = false;
     }

     sumVal += l1Val + l2Val;
     if (0 != (sumVal / 10)) {
         bDeca = true;
         sumVal = sumVal % 10;
     }

     item = new ListNode(sumVal);
     // reset sumVal
     sumVal = 0;
     if (NULL == addedHead) {
         addedHead = item;
     } else {
         ListNode *p = addedHead;
         while (p->next) {
             p = p->next;
         }
         p->next = item;
     }
 }

 return addedHead;
 }
};

汇总

性能一般，需要优化。