自己寫的答案
class Solution {
public:
int romanToInt(string s) {
int sum=0;
for(int i=0;i<s.size();i++){
switch(s[i]){
case 'I':
if(s[i+1]=='V') {sum += 4; i++;}
else if(s[i+1]=='X') {sum += 9; i++;}
else {sum++;}
break;
case 'V':
sum += 5;
break;
case 'X':
if(s[i+1]=='L') {sum += 40; i++;}
else if(s[i+1]=='C') {sum += 90; i++;}
else {sum += 10;}
break;
case 'L':
sum += 50;
break;
case 'C':
if(s[i+1]=='D') {sum += 400; i++;}
else if(s[i+1]=='M') {sum += 900; i++;}
else {sum += 100;}
break;
case 'D':
sum += 500;
break;
case 'M':
sum+= 1000;
break;
}
}
return sum;
}
};
直接按照規(guī)則來就可以了添忘，沒有什么難度。
