Largest Number

Given a list of non negative integers, arrange them such that they form the largest number.

For example, given [3, 30, 34, 5, 9], the largest formed number is 9534330.

Note: The result may be very large, so you need to return a string instead of an integer.

Credits:
Special thanks to @ts for adding this problem and creating all test cases.

1. string to_convert(int a) {
2. stringstream ss;
3. ss << a;
4. string tmp;
5. ss >> tmp;
6. ss.clear();
7. ss.str("");
8. return tmp;
9. }
11. bool cmp(int a,int b) {
12. string tmp1 = to_convert(a);
13. string tmp2 = to_convert(b);
14. string first = tmp1 + tmp2;
15. string second = tmp2 + tmp1;
16. return first>second;
17. }
19. class Solution {
20. public:
21. string largestNumber(vector<int> &num) {
22. sort(num.begin(),num.end(),cmp);
23. string result = "";
24. for(int i=0;i<num.size();i++) {
25. result += to_convert(num[i]);
26. }
27. int pos=0;
28. while(pos<result.size()-1 && result[pos] == '0') pos++;
29. result = result.substr(pos);
30. return result;
31. }
32. };

 

处理对象转换思路更好些