题目来源：http://community.topcoder.com/stat?c=problem_statement&pm=12609

#include <iostream>

#include <string>

using namespace std;

string minstr = "";

class SwappingDigits

{

public: string minNumber(string num);

};

string SwappingDigits::minNumber(string num)

{

	string temp;

	string mins = "";

	for (int i = 0; i < num.size()-1; i++) {

		for (int j = i+1; j < num.size(); j++) {

			temp = num;

			swap(temp[i], temp[j]);

			if (temp[0] != '0' && mins == "") {

				mins = temp;

			} else {

				if (temp[0] != '0' && temp < mins) {

					mins = temp;

				}

			}

		}

	}

	return mins;

}