leetcode算法題--兩數相加 II

原題鏈接：https://leetcode-cn.com/problems/add-two-numbers-ii/

棧

ListNode* addTwoNumbers(ListNode* l1, ListNode* l2) {
    stack<int> s1;//存儲l1
    stack<int> s2;//存儲l2
    while(l1!=NULL){
        s1.push(l1->val);
        l1=l1->next;
    } 
    while(l2!=NULL){
        s2.push(l2->val);
        l2=l2->next;
    } 
    int a,b,c=0;
    ListNode *head=new ListNode(0);
    while(!s1.empty()||!s2.empty()){
        if(!s1.empty()){
            a=s1.top();
            s1.pop();
        }else{
            a=0;
        }
        if(!s2.empty()){
            b=s2.top();
            s2.pop();
        }else{
            b=0;
        }
        int x=(a+b+c)%10;
        c=(a+b+c)/10;
        ListNode *tmp=new ListNode;
        tmp->val=x;
        tmp->next=head->next;
        head->next=tmp;
    }
    if(c!=0){
        head->val=c;
        return head;
    }
    return head->next;
}