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[leetcode] Integer to Roman

时间:2014-06-27 12:41:06      阅读:199      评论:0      收藏:0      [点我收藏+]

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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:构造法,每一位构造然后拼接。每一位表示的字母虽然不同,但是规则是一样的,所以考虑每一位上0-9的表现形式,然后拼接起来。(详见参考1)

思路2:采用贪心策略,每次选择能表示的最大的值,把对应的字符串连接起来,代码及其简洁。

 

贪心:

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));
    }
}

 

 

参考:

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

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

[leetcode] Integer to Roman,布布扣,bubuko.com

[leetcode] Integer to Roman

标签:class   blog   code   java   http   tar   

原文地址:http://www.cnblogs.com/jdflyfly/p/3810685.html

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