2 Add Two Numbers

Add Two Numbers

/**
 * Definition for singly-linked list.
 * struct ListNode {
 *     int val;
 *     ListNode *next;
 *     ListNode(int x) : val(x), next(NULL) {}
 * };
 */
int get_list_len(ListNode* l)
{
    int len = 0;
    ListNode* temp = l;
    while(temp)
    {
        len++;
        temp = temp->next;
    }
    return len;
}

class Solution {
public:
    ListNode* addTwoNumbers(ListNode* l1, ListNode* l2) {
        int l1_len = get_list_len(l1);
        int l2_len = get_list_len(l2);
        int short_len = (l1_len > l2_len) ? l2_len : l1_len;
        ListNode* list_temp = (l1_len > l2_len) ? l1 : l2;
        ListNode* list = list_temp;

        while(short_len)
        {
            short_len --;
            list_temp->val = l1->val + l2->val;
            list_temp = list_temp->next;
            l1 = l1->next;
            l2 = l2->next;
        }

        list_temp = list;
        while(list_temp)
        {
            //printf("%d\n", list_temp->val);
            if(list_temp->val >= 10)
            {
                if(list_temp->next)
                {
                    list_temp->next->val += list_temp->val / 10;
                }
                else
                {
                    list_temp->next = new ListNode(list_temp->val / 10);
                }
                list_temp->val = list_temp->val % 10;
            }
            list_temp = list_temp->next;
        }

        return list;
    }
};

void trimLeftTrailingSpaces(string &input) {
    input.erase(input.begin(), find_if(input.begin(), input.end(), [](int ch) {
        return !isspace(ch);
    }));
}

void trimRightTrailingSpaces(string &input) {
    input.erase(find_if(input.rbegin(), input.rend(), [](int ch) {
        return !isspace(ch);
    }).base(), input.end());
}

vector<int> stringToIntegerVector(string input) {
    vector<int> output;
    trimLeftTrailingSpaces(input);
    trimRightTrailingSpaces(input);
    input = input.substr(1, input.length() - 2);
    stringstream ss;
    ss.str(input);
    string item;
    char delim = ',';
    while (getline(ss, item, delim)) {
        output.push_back(stoi(item));
    }
    return output;
}

ListNode* stringToListNode(string input) {
    // Generate list from the input
    vector<int> list = stringToIntegerVector(input);

    // Now convert that list into linked list
    ListNode* dummyRoot = new ListNode(0);
    ListNode* ptr = dummyRoot;
    for(int item : list) {
        ptr->next = new ListNode(item);
        ptr = ptr->next;
    }
    ptr = dummyRoot->next;
    delete dummyRoot;
    return ptr;
}

string listNodeToString(ListNode* node) {
    if (node == nullptr) {
        return "[]";
    }

    string result;
    while (node) {
        result += to_string(node->val) + ", ";
        node = node->next;
    }
    return "[" + result.substr(0, result.length() - 2) + "]";
}

int main() {
    string line;
    while (getline(cin, line)) {
        ListNode* l1 = stringToListNode(line);
        getline(cin, line);
        ListNode* l2 = stringToListNode(line);

        ListNode* ret = Solution().addTwoNumbers(l1, l2);

        string out = listNodeToString(ret);
        cout << out << endl;
    }
    return 0;
}

输入：[2,4,3] [5,6,4]
输出：[7, 0, 8]