Leetcode Note: Integer to Roman

Leetcode Note: Integer to Roman

I. Description

Given a roman numeral, convert it to an integer.
Input is guaranteed to be within the range from 1 to 3999.

Ii. Question Analysis

Roman numerals summary:

1 ~ 9: {"I", "II", "III", "IV", "V", "VI", "VII", "VIII", "IX "};

10 ~ 90: {"X", "XX", "XXX", "XL", "L", "LX", "LXX", "LXXX", "XC "};

100 ~ 900: {"C", "CC", "CCC", "CD", "D", "DC", "DCC", "DCCC", "CM "};

1000 ~ 3000: {"M", "MM", "MMM "}.

For more information about the Roman number system, see: http://baike.baidu.com/view/1246899.htm

This problem is to enter an Arabic number and convert it to a Roman numeric string.

You can use the simplest operation, that is, to take the low to high digits for the operation. Take one digit at a time, divide the number by 10 after obtaining one digit, and represent the digit with a Roman number. Note that if the current digit is not the original number, you need to increase it by 10 times or 100 times.

Iii. Sample Code

class Solution {public:    string intToRoman(int num) {        string str;          string symbol[]={M,CM,D,CD,C,XC,L,XL,X,IX,V,IV,I};          int value[]=    {1000,900,500,400, 100, 90,  50, 40,  10, 9,   5,  4,   1};         for(int i=0;num!=0;++i)        {            while(num>=value[i])            {                num-=value[i];                str+=symbol[i];            }        }        return str;    }};