Largest Number

Description：

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.

Code：

 1  int islesseq(int&a, int&b)

 2     {

 3         stringstream ss;

 4         string strA, strB;

 5         

 6         ss << a;

 7         ss >> strA;

 8         ss.clear();

 9         ss << b;

10         ss >> strB;

11         

12         if (strA+strB <= strB+strA)

13         {

14             return 1;

15         }

16         else

17             return 0;

18     }

19     

20     int partition(vector<int>&nums, int low, int high)

21     {

22         int key = nums[low];

23         while (low<high)

24         {

25             while (low < high && islesseq(key,nums[high]))--high;

26             nums[low] = nums[high];

27             while (low < high && islesseq(nums[low],key))++low;

28             nums[high] = nums[low];

29         }

30         nums[low] = key;

31         return low;

32     }

33     

34     void sort(vector<int>&nums, int low, int high)

35     {

36         if (low < high)

37         {

38             int pivot = partition(nums,low, high);

39             sort(nums,low,pivot-1);

40             sort(nums, pivot+1, high);

41         }

42     }

43     

44     string largestNumber(vector<int>& nums) {

45         sort(nums,0, nums.size()-1);

46         if (nums[nums.size()-1] == 0)

47             return "0";

48         stringstream ss;

49         for (int i = nums.size()-1; i >= 0; --i)

50         {

51             ss<<nums[i];

52         }

53         return ss.str();

54     }

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