The Next Permutation http://acm.hdu.edu.cn/webcontest/contest_showproblem.php?cid=8154&pid=1004&ojid=1

1004.cpp

#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <algorithm>
#include <functional>

using namespace std;

#define  MAX_LENGTH  1000

int main()
{
    int test_cases;
    static char number[MAX_LENGTH];
    scanf("%d", &test_cases);
    for (int i = 1; i <= test_cases; ++ i)
    {
        scanf("%*d %s", number);
        int len = strlen(number);
        bool found_greater = false;
        bool all_equal = true;
        for (int j = len - 2; j >= 0; -- j)
        {
            if (number[j] == number[j+1])
                continue;
            all_equal = false;
            if (number[j] < number[j+1])
            {
                found_greater = true;
                char smallest = '9' + 1;
                int smallest_subscript = 0;
                for (int k = j + 1; k < len; ++ k)
                {
                    if (number[k] > number[j] && number[k] < smallest)
                    {
                        smallest = number[k];
                        smallest_subscript = k;
                    }
                }
                swap(number[j], number[smallest_subscript]);
                sort(&number[j+1], &number[len]);
                break;
            }
        }
        if (all_equal || found_greater)
            printf("%d %s\n", i, number);
        else
            printf("%d BIGGEST\n", i);
    }
    return EXIT_SUCCESS;
}