roman to integer

问题：将给定的罗马字符串转换为整数。

class Solution {public:int romanToInt(string s) {if(s.size() == 0) return 0;        int re = 0;//index 表示当前应该处理的元素。int index = 0;int len = s.size();//处理跟M有关的数    int thousand = s.find_first_of('M');if (-1 != thousand ){//find if( thousand == 0){//it's "M****"//处理连续M,连续则累加。while(index < len && s[index] == 'M'){re += 1000;++index;}//出现不连续的M，则是900.thousand = s.find_last_of('M');if (thousand > index){re += 900;index = thousand + 1;}if(index == len) return re;}else{//M没在第一位，则表示的数是介于[900,1000)re += 900;index = thousand + 1;}}//处理跟D有关的数，[400,900)int five_hun = s.find_first_of('D');if ( -1 != five_hun){if(five_hun == index){// >= 500re += 500;index++;}else{// it must be "CD"re += 400;index = five_hun + 1;}}//处理跟C有关的数[90, )int hun = s.find_first_of('C');if (hun >= index){if (hun == index){//C前面没有X，[100, )while (index < len && s[index] == 'C'){ re += 100;++index;}hun = s.find_last_of('C');if (hun > index){re += 90;index = hun + 1;}if(index == len) return re;}else{//it must be "XC"re += 90;index = hun + 1;}}//handle 'L'int five_ten = s.find_first_of('L');if (five_ten >= index){if (five_ten == index){//"V***"re += 50;index++;if(index == len) return re;}else{//"XV"re += 40;index = five_ten + 1;}}//handle the Xint ten = s.find_first_of('X');if (ten >= index){if (ten == index && s[index + 1] == 'C'){re += 90;index += 2;}else if (ten == index){while (index < len && s[index] == 'X'){re += 10; ++index;}ten = s.find_last_of('X');//"IX"if (ten > index){re += 9;index = ten + 1;}if(index == len) return re;}else {re += 9;index = ten + 1;}}//handle 'V'int five = s.find_first_of('V');if (five >= index){if(five == index){re += 5;index++;}else{re += 4;index = five + 1;}}int ge = s.find_first_of('I');if(index > len - 1) return re;if(ge < len - 1 && s[ge + 1] == 'X'){re += 9;return re;}    while (ge != -1 && ge <= len - 1)    { re += 1; ge++; }return re;}};

花了一晚上的时间，写出如此代码，真真说不过去了，烂的一塌糊涂。