[leetcode] Integer to Roman

Given an integer, convert it to a roman numeral. html

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

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

思路1:構造法,每一位構造而後拼接。每一位表示的字母雖然不一樣,可是規則是同樣的,因此考慮每一位上0-9的表現形式,而後拼接起來。(詳見參考1) ide

思路2:採用貪心策略,每次選擇能表示的最大的值,把對應的字符串鏈接起來,代碼及其簡潔。 ui


貪心: idea

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: .net

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

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

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