leetcode-12-Integer-to-Roman

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描述

Given an integer, convert it to a roman numeral.

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

分析

这道题和 leetcode-13-Roman-to-Integer 是联系的，罗马数字转换为阿拉伯数字，在 leetcode-13-Roman-to-Integer 中已有介绍，阿拉伯数字转换为罗马数字，可以将罗马字母的值从大到小排列出来，依次对应即可。

解决方案1(C++)

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

解决方案2(Rust)

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impl Solution {
    pub fn int_to_roman(num: i32) -> String {
       let symble: Vec<(i32, &'static str)> = vec![
            (1000, "M"),
            (900, "CM"),
            (500, "D"),
            (400, "CD"),
            (100, "C"),
            (90, "XC"),
            (50, "L"),
            (40, "XL"),
            (10, "X"),
            (9, "IX"),
            (5, "V"),
            (4, "IV"),
            (1, "I"),
        ];
        
        let mut num = num;
        let mut result = String::new();
        for p in symble.iter() {
            if num >= p.0 {
                for _ in 0..(num / p.0) {
                    result.push_str(p.1);
                }
                num = num % p.0
            }
        }
        result
    }
}

相关问题

(E) Roman to Integer
(H) Integer to English Words

题目来源