uva 759 - The Return of the Roman Empire

 

#include <cstdio>
#include <string>
#include <map>
using namespace std;

const int SIZE = 13;
const int value[] = {1, 4, 5, 9, 10, 40, 50, 90, 100, 400, 500, 900, 1000};
const string sign[] = {"I", "IV", "V", "IX", "X", "XL", "L", "XC", "C", "CD", "D", "CM", "M"};

int main()
{
    map<string, int> dic;
    for (int n = 1; n < 4000; n++)
    {
        int num = n;
        string Roman = "";
        for(int i = SIZE - 1; i >= 0 && num; i--)
        {
            while(num >= value[i])
            {
                Roman += sign[i];
                num -= value[i];
            }
        }
        dic[Roman] = n;
    }

    char s[99];
    while(gets(s))
    {
        if(s[0] == '\0')
        {
            puts("0");
            continue;
        }
        if(dic.count(s)) printf("%d\n", dic[s]);
        else printf("This is not a valid number\n");
    }
    return 0;
}