题解 | #大数加法#

class Solution {
public:

    string solve(string s, string t) {
        string ret;
        int count = 0;
        int i = s.size()-1;
        int j = t.size()-1;
        while(i>=0 || j>=0 || count)
        {
            if(i>=0) count += s[i--] - '0';
            if(j>=0) count += t[j--] - '0';
            ret.push_back((count%10)+'0');
            count /= 10;
        }
        reverse(ret.begin(),ret.end());
        return ret;
    }
};