To rank the array into the smallest number

The title description enters an array of positive integers, stitching up all the numbers in the array into a number, and printing the smallest of all the numbers that can be stitched together. For example, enter the array {3,32,321}, then print out the minimum number that these three numbers can be ranked as 321323.
/*对vector容器内的数据进行排序，按照 将a和b转为string后   若 a＋b<b+a  a排在在前 的规则排序,   如 2 21 因为 212 < 221 所以 排序后为 21 2     to_string() 可以将int 转化为string */

Class Solution {public:    static BOOL cmp (int a,int b) {        string a= "";        String b= "";        A+=to_string (a);        A+=to_string (b);        B+=to_string (b);        B+=to_string (a);        Return a<b;    }        String Printminnumber (vector<int> numbers) {        string answer= "";        Sort (Numbers.begin (), Numbers.end (), CMP);        for (int i=0;i<numbers.size (); i++) {            answer+=to_string (numbers[i]);        }        return answer;}                    ;

　　

Class Solution {public:    string printminnumber (vector<int> numbers) {        string result;       int length=numbers.size ();        if (length<=0)             return Result;       stringstream stream;        //string *str=new string[length];       vector<string > vec;       for (int i=0;i<length;i++)          {            //Method 1: Use To_ String converts a number to a string             vec.push_back (to_string (Numbers[i]));             //Method 2: Convert numbers to strings with the help of a string stream StringStream nbsp;            /*string str;             stream<<numbers[i];             stream>>str;             vec.push_back (str);             stream.clear ();  //Remember to clear              */        }        sort (Vec.begin (), Vec.end (), comp);        for (int i=0; i<length;i++)          {              result+=vec[i];          }        return result;    }     static BOOL Comp (string str1,string str2)  // If the comp function is placed outside, the static keyword can be removed for the following reasons:     {                            The comparison function in   //sort compare to be declared as a static member function or a global function, not as a normal member function, or an error will be made.                                     // Because a non-static member function is dependent on a specific object, and the Std::sort function is global, it is no longer possible to sort the         string s1= str1+str2;      //with non-static member functions. A static member function or global function is independent of the object and can be accessed independently without creating any         string s2=str2+str1;  The      //object instance can be accessed. Static member functions can not invoke non-static members of the class at the same time.         return S1&Lt;s2;     }}; 

　　

http://blog.csdn.net/fanzitao/article/details/7895344

http://blog.csdn.net/taoyanqi8932/article/details/52541312

Class Solution {public:string printminnumber (vector<int> numbers) {sort (Numbers.begin (), Numbers.end (),        [] (const int& A,const int& b) {return to_string (a) +to_string (b) <to_string (b) +to_string (a);});        string res;        for (auto C:numbers) res+=to_string (c);    return res; }};

　　

To rank the array into the smallest number