题解 | #链表相加(二)#大数加法过来的#

 * Definition for singly-linked list.
 * struct ListNode {
 *     int val;
 *     ListNode *next;
 *     ListNode(int x) : val(x), next(NULL) {}
 * };
 */

class Solution {
public:
        string solve(string s, string t) 
        {
        // write code here
        int len_s_ = s.size();
        int len_t_ = t.size();
        
        int jinwei=0;//进位
        int gewei = 0;//个位
        
        stack<char> res;
        
        for(int i=len_s_-1,j=len_t_-1;i>=0||j>=0;i--,j--)
        {
            int s_n = '0',t_n='0';
            
            if(i>=0) s_n = s[i];
            
            if(j>=0) t_n = t[j];
            
            int now = s_n-'0'+t_n-'0'+jinwei;
            
            jinwei = now/10;
            now%=10;
            
            res.push(now+'0');
        }
        
        if(jinwei!=0) res.push(jinwei+'0');
        
        string res_;
        
        while(!res.empty()) 
        {
            res_.push_back(res.top());
                res.pop();
        }
        
        return res_;
    }
    
    string int_generate_str(ListNode* p)
    {
        string res;
        
        for(ListNode* tmp = p;tmp!=nullptr;tmp=tmp->next)
            res+='0'+tmp->val;


        return res;
    }
    
    ListNode* str_transfer_list(string str)
    {
        ListNode* res = new ListNode(-1);
        ListNode* point = res;
        
        for(char c:str)
        {
            ListNode* p=new ListNode(c-'0');
            point->next = p;
            point = point->next;
        }
        
        return res->next;
    }
    
    ListNode* addInList(ListNode* head1, ListNode* head2) {
        
        return str_transfer_list(solve(int_generate_str(head1), int_generate_str(head2)));
    }
};