排序上的段错误

Question

class Solution {
public:
    string largestNumber(vector<int>& nums) {
        vector<string> tmp;
        string ans;

        for (size_t i = 0; i < nums.size(); ++i) 
            tmp.push_back(to_string(nums[i]));

        sort(tmp.begin(), tmp.end(),
             bind(&Solution::compare,
                  this, placeholders::_1, placeholders::_2));

        for (auto it = tmp.rbegin(); it != tmp.rend(); ++it) 
            ans += *it;

        return ans;
    }

private:
    bool compare(const string &lhs, const string &rhs) {
        if (lhs.size() > rhs.size())
            return !compare(rhs, lhs);

        int len1 = lhs.size();
        int len2 = rhs.size();

        if (lhs[0] != rhs[0]) {
            return lhs[0] < rhs[0];
        } else {
            if (len1 != 1) {
                return compare(lhs.substr(1), rhs.substr(1));
            } else {
                auto pos = rhs.find_first_not_of(lhs[0]);
                if (pos != string::npos) 
                    return lhs[0] < rhs[pos];
            }
        }

        return true;
    }
};

int main(int argc, char **argv)
{
    vector<int> input2 = {0,0,0,0,0,0,0,0,0,0,0,0,
                          0,0,0,0,0,0,0,0,0,0,0,0,
                          0,0,0,0,0,0,0,0,0,0,0,0,
                          0,0,0,0,0,0,0,0,0,0,0,0,
                          0,0,0,0,0,0,0,0,0,0,0,0,
                          0,0,0,0,0,0,0,0,0,0,0,0,
                          0,0,0,0,0,0,0,0,0,0,0,0,
                          0,0,0,0,0,0,0,0,0,0,0,0,
                          0,0,0,0};

    string target2 = string(input2.size(), '0');

    Solution sln;

    assert(sln.largestNumber(input2) == target2);

    return 0;
}

这是leetcode 179的问题，代码正在运行并在ubuntu上使用g ++构建。当向量是较小的向量时，代码进展顺利。但是，当向量较大时，该过程将在排序行中存在段错误。结果很模糊，我想知道我的代码有什么问题。