leetcode Roman Integer

class Solution {

 public:

  int romanToInt(string s) {

    if (s.length() < 1)

      return 0;

    map<char,int> m;

	m['I'] = 1;

	m['V'] = 5;

	m['X'] = 10;

	m['L'] = 50;

	m['C'] = 100;

	m['D'] = 500;

	m['M'] = 1000;

    int i = s.length() - 1;

    int sum = m[s[i--]];

    while (i >= 0) {

      if (m[s[i + 1]] > m[s[i]])

        sum -= m[s[i]];

      else

        sum += m[s[i]];

      --i;

    }

    return sum;

  }

};

class Solution {

 public:

  string intToRoman(int num) {

    // IMPORTANT: Please reset any member data you declared, as

    // the same Solution instance will be reused for each test case.

    string symbol[]={"M","CM","D","CD","C","XC","L","XL","X","IX","V","IV","I"};

    int value[]={1000,900,500,400,100,90,50,40,10,9,5,4,1};

    string res = "";

    int i = 0;

    while (num > 0) {

      if (num >= value[i]) {

        res += symbol[i];

        num -= value[i];

      }

      else

        ++i;

    }

    return res;

  }

};

巴特西

leetcode Roman Integer

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