[leetcode] Integer to Roman

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Given an integer, convert it to a roman numeral.

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

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

思路1：構造法，每一位構造然後拼接。每一位表示的字母雖然不同，但是規則是一樣的，所以考慮每一位上0-9的表現形式，然後拼接起來。（詳見參考1）

思路2：採用貪心策略，每次選擇能表示的最大的值，把對應的字串串連起來，代碼及其簡潔。

 

貪心：

public class Solution {    public String intToRoman(int num) {        String[] str = new String[] { "M", "CM", "D", "CD", "C", "XC", "L", "XL", "X", "IX", "V", "IV", "I" };        int[] val = new int[] { 1000, 900, 500, 400, 100, 90, 50, 40, 10, 9, 5, 4, 1 };        StringBuilder sb = new StringBuilder();        for (int i = 0; num > 0; i++) {                        while (num >= val[i]) {                num -= val[i];                sb.append(str[i]);            }        }        return sb.toString();    }        public static void main(String[]args){        System.out.println(new Solution().intToRoman(999));    }}

 

 

參考：

http://www.cnblogs.com/zhaolizhen/p/romannumber.html

http://blog.csdn.net/havenoidea/article/details/11848921