[LeetCode][JavaScript]Integer to Roman

Integer to Roman

Given an integer, convert it to a roman numeral.

Input is guaranteed to be within the range from 1 to 3999.

https://leetcode.com/problems/integer-to-roman/

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阿拉伯数字转罗马数字。

造表，把有所的基数都放到表中，主要是要放入IV，IX这类数，方便处理。

从大到小匹配表中的数，一轮循环搞定。

/**
 * @param {number} num
 * @return {string}
 */
var intToRoman = function(num) {
    var number = [1,   4,    5,   9,    10,  40,   50,  90,   100, 400,  500, 900,  1000];
    var roman =  ["I", "IV", "V", "IX", "X", "XL", "L", "XC", "C", "CD", "D", "CM", "M"];
    var tmp, index = 12, res = ""; 
    while(index >= 0){
        if(number[index] > num){
            index--;
            continue;
        }
        while(num >= number[index]){
            num -= number[index];
            res += roman[index];
        }
        index--;
    }
    return res;
};