Morris' Blog 我在摸索我存在的意義、生命的意義、內涵及價值。 沒有真正神手般的厲害，套用模式是大部分的情況。 沒那麼厲害的我存在的意義為何，襯托出神的存在？ 有時候不能怪別人不給我機會，我已經開始省思， 為什麼我沒有給別人機會的原因，而是全要靠別人。 有時候我認為我與眾不同，那是因為我做不到很多人能辦到的事情。 我聽不到、玩不起來、說得不夠明瞭、理解得不夠多， 我缺少的語文能力，就是一切一切無能的判定。 為此，我不曉得能做些對別人有幫助的事情。 我知道我自己是個不服輸的性格，但現在我不得不認輸。 我沒有能力，因此我必須認輸。 我到底來這世界作什麼？處處充滿不確定性， 而我總是無法出類拔萃，想當個一般人似乎也回不了頭了。 越強大的挑戰需要越強力的支持，而我的支持是什麼？ 最近嘗試與人談話，但都是失敗的結局，沒人能接受， 不需要言語，不需要溝通，一切所想都表達不出來。

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Context

This year is the XXV Anniversary of the Faculty of Computer Science in Murcia. But, what XXV means? Maybe you should ask an ancient Roman to get the answer.

The Problem

A Roman numeral consists of a set of letters of the alphabet. Each letter has a particular value, as shown in the following table:

Letter	I	V	X	L	C	D	M
Value	1	5	10	50	100	500	1000

Generally, Roman numerals are written in descending order from left to right, and are added sequentially. However, certain combinations employ a subtractive principle. If a symbol of smaller value precedes a symbol of larger value, the smaller value is subtracted from the larger value, and the result is added to the total. This subtractive principle follows the next rules:

• "I" may only precede "V" and "X" (e.g., IV=4).
• "X" may only precede "L" and "C" (e.g., XC=900).
• "C" may only precede "D" and "M".
• "V", "L" and "D" are always followed by a symbol of smaller value, so they are always added to the total.

Symbols "I", "X", "C" and "M" cannot appear more than three consecutive times. Symbols "V", "L" and "D" cannot appear more than once consecutively.

Roman numerals do not include the number zero, and for values greater or equal than 4000 they used bars placed above the letters to indicate multiplication by 1000.

You have write a program that converts from Roman to Arabic numerals and vice versa. Although lower case letters were used in the Middle Ages, the Romans only used upper case letters. Therefore, for the Roman numerals we only consider upper case letters.

The Input

The input consists of several lines, each one containing either an Arabic or a Roman number n, where 0 < n < 4000.

The Output

For each input line, you must print a line with the converted number. If the number is Arabic, you must give it in Roman format. If the number is Roman, you must give it in Arabic format.

Sample Input

XXV
4
942
MCMLXXXIII

Sample Output

25
IV
CMXLII
1983

---

#include <stdio.h>
#include <iostream>
#include <map>
using namespace std;

char* toRoman(int num) {
    const char rcode[13][3] = {"M", "CM", "D", "CD", "C", "XC", "L",
                        "XL", "X", "IX", "V", "IV", "I"};
    const int val[13] = {1000, 900, 500, 400, 100, 90, 50,
                        40, 10, 9, 5, 4, 1};
    char *roman = new char[30], idx = 0;
    int i;
    for(i = 0; i < 13; i++) {
        while(num >= val[i]) {
            num -= val[i];
            roman[idx++] = rcode[i][0];
            if(rcode[i][1] != '\0')
                roman[idx++] = rcode[i][1];
        }
    }
    roman[idx] = '\0';
    return roman;
}
int main() {
    int n;
    char *str, in[50];
    map<string, int> ch1;
    map<int, string> ch2;
    for(n = 1; n <= 4000; n++) {
        str = toRoman(n);
        ch1[str] = n;
        ch2[n] = str;
        delete[] str;
    }
    while(scanf("%s", in) == 1) {
        if(in[0] >= '0' && in[0] <= '9') {
            sscanf(in, "%d", &n);
            cout << ch2[n] << endl;
        } else
            cout << ch1[in] << endl;
    }
    return 0;
}