- 两两转化为字符串相加再相比以决定谁在前面
class Solution {
public:
string largestNumber(vector<int> &num) {
vector<string> arr;
for(auto i:num)
arr.push_back(to_string(i));
sort(begin(arr), end(arr), [](string &s1, string &s2){ return s1+s2>s2+s1; });
string res;
for(auto s:arr)
res+=s;
while(res[0]=='0' && res.length()>1)
res.erase(0,1);
return res;
}
};