leetcode--conversion of Roman numerals and Arabic numerals

To tell you the truth, these two words marked as medium and simple on the leetcode have made my egg ache for half a day. Probably because of the congenital to the Arabic numeral unfamiliar relationship, so in do two questions incredibly not a little feeling!!!!!

Converting Roman numerals to Arabic numerals is simple: scanning the entire string from left to right can be done only when the previous number is smaller than the latter and requires special processing (subtraction required).

Class solution {public:int romantoint (string s) {if  (S.empty ()) {return 0;} int letter[256];for  (int i=0; i<256; i++) {letter[i] = 0;} letter[' I '] = 1;letter[' V '] = 5;letter[' X '] = 10;letter[' L '] = 50; letter[' C '] = 100;letter[' D '] = 500;letter[' M '] = 1000;int result =  0;unsigned int cur = 0;unsigned int next = 1;while  (Next  < s.size ()) {if  (Letter[s[cur]] < letter[s[next]) {Result = result  +  (Letter[s[next]] - letter[s[cur]]);cur = cur + 2;next =  Next + 2;} else{result = result + letter[s[cur]];cur = cur + 1;next =  next + 1;}} if  (Cur < s.size ()) {result = result + letter[s[cur]];} return result;}};

Convert Arabic numerals to Roman numerals some of the eggs hurt .... But saw the Leetcode on the highest vote of a method, the original also only need to be thousands, hundred, 10 and so on to express out both.

Class solution {public:    string inttoroman (Int num)  {         string result =  "";         if  (num < 1 | |  num > 3999)         {             return result;        }         string m[] = {"",  "M",  "MM",  " MMM "};    //thousand, from 1000 to 3000        string c[]  = {"",  "C",  "CC",  "CCC",  "CD",  "D",  "DC",  "DCC",  "DCCC",   "CM"};  //hundred, from 100 to 900        string x[] =  {"",  "X",  "XX",  "XXX",  "XL",  "L",  "LX",  "LXX ", " LXXX ", " XC "};  //10-bit, from 10 to 90        string  i[] = {"",  "I",  "II",  "III",  "IV",  "V",  "VI",  "VII",  " VIII ", " IX "};  //bits, from 1 to 9        result = m[ num / 1000] + c[(num % 1000)  / 100] + x[(num % 100 )  / 10] + I[num % 10];    }};

leetcode--conversion of Roman numerals and Arabic numerals