Topcoder SRM583 DIV 2 250

 #include <string>
 #include <iostream>
 using namespace std;

 class SwappingDigits
 {
 public:
     bool notBiggest(string &s,int pos)
     {
         int len=s.length();
         int i=;
         for (i=pos+;i<len;i++)
         {
             if (s[i]<s[pos]&&(s[i]!=''||pos!=))
             {
                 return true;
             }
         }
         return false;
     }
     int findSmallest(string&s,int pos)
     {
         int len=s.length();
         int i=;
         char c='';
         int index;
         for (i=len-;i>pos;i--)
         {
             if (s[i]<c&&(s[i]!=''||pos!=))
             {
                 c=s[i];
                 index=i;
             }
         }
         return index;
     }
     string minNumber(string num)
     {
         int i;
         int len=num.length();
         for (i=;i<len-;i++)
         {
             if (notBiggest(num,i))
             {
                 int index=findSmallest(num,i);
                 char c=num[index];
                 num[index]=num[i];
                 num[i]=c;
                 break;
             }
         }
         return num;
     }
 };
 int main()
 {
     SwappingDigits sol;
     string s;
     while(true)
     {
         cin>>s;
         cout<<sol.minNumber(s)<<endl;
     }
 }