leetcode刷题4——整数与罗马数字互转系列

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本文介绍了如何使用查表法实现整数到罗马数字及罗马数字到整数的转换，并提供了具体的C++代码实现。

1.整数转罗马数字
考察知识点：查表法

class Solution {
public:
    string intToRoman(int num) {
        int values[]={1000,900,500,400, 100,90,50,40, 10,9,5,4,1};
        string reps[]={"M","CM","D","CD","C","XC","L","XL","X","IX","V","IV","I"};
        string s="";
        for(int i=0;i<13;++i)
        {
            while(num>=values[i])
            {
                num-=values[i];
                s+=reps[i];
            }
        }
        return s;
    }
};

2.罗马数字转整数
考察知识点：查表法

class Solution {
public:
    int romanToInt(string s) {
        int values[]={1000,900,500,400,100,90,50,40,10,9,5,4,1};
        string reps[]={"M","CM","D","CD","C","XC","L","XL","X","IX","V","IV","I"};
        int num=0;
        for(int i=0;i<13;i++)
        {
            while(s.find(reps[i])==0)
            {
                num+=values[i];
                s=s.substr(reps[i].length());
            }
        }
        return num;
    }