Roman to Integer
class Solution { public: int romanToInt(string s) { int data[26] = {0}; data['I'-'A'] = 1; data['V'-'A'] = 5; data['X'-'A'] = 10; data['L'-'A'] = 50; data['C'-'A'] = 100; data['D'-'A'] = 500; data['M'-'A'] = 1000; int result = 0; int value = 0; int i= 0; for( i=0; i<s.size()-1;i++) { if(s[i]<'A' || s[i] >'Z') return 0; if(data[s[i]-'A'] >= data[s[i+1]-'A']) { result +=data[s[i]-'A']; } else { result += data[s[i+1]-'A'] - data[s[i]-'A']; i++; } } if(i == s.size()-1) { result += data[s[i]-'A'] ; } return result; } };