LeetCode 179. Largest Number

把数字转换成字符串，给这些字符串排个序，排出的序列即为拼接顺序。

sort(strs.begin(), strs.end(), [](string a, string b) -> bool{return (a + b) > (b + a);});

代码：

class Solution{public:string largestNumber(vector<int> &num){vector<string> strs(num.size());for (size_t i = 0; i < num.size(); ++i){strs[i] = int_to_string(num[i]);}sort(strs.begin(), strs.end(), [](string a, string b) -> bool{return (a + b) > (b + a);});string ret;for (const auto& str : strs){ret += str;}return ret[0]=='0'? "0": ret;}private:string int_to_string(int num){stringstream ss;ss << num;string str;ss >> str;return str;}};