12. 整数转罗马数字

难度中等878

罗马数字包含以下七种字符： I， V， X， L，C，D 和 M。

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字符          数值
I             1
V             5
X             10
L             50
C             100
D             500
M             1000

例如， 罗马数字 2 写做 II ，即为两个并列的 1。12 写做 XII ，即为 X   II 。 27 写做  XXVII, 即为 XX   V   II 。

通常情况下，罗马数字中小的数字在大的数字的右边。但也存在特例，例如 4 不写做 IIII，而是 IV。数字 1 在数字 5 的左边，所表示的数等于大数 5 减小数 1 得到的数值 4 。同样地，数字 9 表示为 IX。这个特殊的规则只适用于以下六种情况：

• I 可以放在 V (5) 和 X (10) 的左边，来表示 4 和 9。
• X 可以放在 L (50) 和 C (100) 的左边，来表示 40 和 90。 
• C 可以放在 D (500) 和 M (1000) 的左边，来表示 400 和 900。

给你一个整数，将其转为罗马数字。

示例 1:

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输入: num = 3
输出: "III"

示例 2:

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输入: num = 4
输出: "IV"

示例 3:

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输入: num = 9
输出: "IX"

示例 4:

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输入: num = 58
输出: "LVIII"
解释: L = 50, V = 5, III = 3.

示例 5:

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输入: num = 1994
输出: "MCMXCIV"
解释: M = 1000, CM = 900, XC = 90, IV = 4.

提示：

• 1 <= num <= 3999

通过次数294,938提交次数445,122

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code

string  mm[4][11] ={
        {"","I","II","III","IV","V","VI","VII","VIII","IX" },
        {"","X","XX","XXX","XL","L","LX","LXX","LXXX","XC"},
        {"","C","CC","CCC","CD","D","DC","DCC","DCCC","CM"},
        {"","M","MM","MMM"}
    };

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class Solution {
public:
    string  mm[4][11] ={
        {"","I","II","III","IV","V","VI","VII","VIII","IX" },
        {"","X","XX","XXX","XL","L","LX","LXX","LXXX","XC"},
        {"","C","CC","CCC","CD","D","DC","DCC","DCCC","CM"},
        {"","M","MM","MMM"}
    };
    string intToRoman(int num) {
            int pos=0;
            int idx=0;
            //int num=0;
            string str[100];
            string ans;
            while(num!=0){
                int cur=num;
                if(cur!=0){
                    str[idx]=mm[pos][cur];
                    idx  ;
                }
                pos  ;
                num=num/10;
            }
            //ans=str[0];
            while(idx>=0){
                ans =str[idx];
                idx--;
            }
            return ans;
    }
};

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#include <stdio.h>
#include <iostream>
using namespace std;
#include <climits>
string intToRoman(int num);

int main(void) {
	cout<<intToRoman(588)<<endl;
    return 0;
}

string  mm[4][11] ={
        {"","I","II","III","IV","V","VI","VII","VIII","IX" },
        {"","X","XX","XXX","XL","L","LX","LXX","LXXX","XC"},
        {"","C","CC","CCC","CD","D","DC","DCC","DCCC","CM"},
        {"","M","MM","MMM"}
    };
    string intToRoman(int num) {
            int pos=0;
            int idx=0;
            //int num=0;
            string str[100];
            string ans;
            while(num!=0){
                int cur=num;
                if(cur!=0){
                    str[idx]=mm[pos][cur];
                    idx  ;
                }
                pos  ;
                num=num/10;
            }
            //ans=str[0];
            while(idx>=0){
                ans =str[idx];
                idx--;
            }
            return ans;
    }

int string vi

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