Codeforces Beta Round #34. Task C

#include <cstdio>
#define N 1002

bool print[N];

int main()
{
    while (1)
    {
        int num;
        scanf("%d", &num);
        print[num] = true;
        if (scanf(",") == -1) break;
    }

    int start = 0;
    bool first = true;

    for (int i = 1; i < N; i++)
    {
        if (print[i])
            if (!start) start = i;
        if (!print[i])
        {
            if (start)
            {
                if (first)
                    first = false;
                else
                    printf(",");

                int finish = i - 1;
                if (start == finish)
                    printf("%d", start);
                else
                    printf("%d-%d", start, finish);

                start = 0;
            }
        }
    }

    return 0;
}