[LeetCode] Largest Number

 1 bool cmp(const string s1, const string s2) {
 2     return (s1 + s2) > (s2 + s1);
 3 }
 4 
 5 class Solution {
 6 public:
 7     string largestNumber(vector<int> &num) {
 8         vector<string> s_num(num.size());
 9         stringstream stream;
10         for (int i = 0; i < num.size(); ++i) {
11             stream << num[i];
12             stream >> s_num[i];
13             stream.clear();
14         }
15         sort(s_num.begin(), s_num.end(), cmp);
16         string tmp_res;
17         for (int i = 0; i < s_num.size(); ++i) {
18             tmp_res += s_num[i];
19         }
20         string res;
21         bool flag = false;
22         for (int i = 0; i < tmp_res.size(); ++i) {
23             if (tmp_res[i] != ‘0‘) {
24                 res.push_back(tmp_res[i]);
25                 flag = true;
26             } else if (flag) {
27                 res.push_back(tmp_res[i]);
28             }
29         }
30         if (!flag) res.push_back(‘0‘);
31         return res;
32     }
33 };