Leetcode record-convert the number of Rome to an integer

The number contains the following seven characters:I,V,X,L,C,DAndM.

Character value I 1 V 5x 10l 50C 100d 500 m 1000

For example, write the number 2 in RomeII, That is, two parallel 1. 12 writeXII, That isX+II. 27 writeXXVII, That isXX+V+II.

Generally, a small number is on the right of a large number. But there are also special cases, for example, do not write 4IIII,IV. The number 1 is on the left of number 5, and the number is equal to the number 5. Reduce the number 1 to get the value 4. Similarly, Number 9 indicatesIX. This special rule applies only to the following six cases:

• ICan be placed inV(5) andXThe left side of (10) indicates 4 and 9.
• XCan be placed inL(50) andCThe left side of (100) indicates 40 and 90.
• CCan be placed inD(500) andMThe left side of (1000) indicates 400 and 900.

Converts a roman number to an integer. Make sure that the input is within the range of 1 to 3999.

Example 1:

Input: "III" output: 3

Example 2:

Input: "IV" output: 4

Example 3:

Input: "IX" output: 9

Example 4:

Input: "LVIII" output: 58 explanation: L = 50, V = 5, III = 3.

Example 5:

Input: "mcmxciv" output: 1994 explanation: M = 1000, Cm = 900, XC = 90, IV = 4.



Answer:

class Solution {    public int romanToInt(String s) {         int sum=0;        char[] schar=s.toCharArray();        Map map =new HashMap();        map.put(‘I‘,1);        map.put(‘V‘,5);        map.put(‘X‘,10);        map.put(‘L‘,50);        map.put(‘C‘,100);        map.put(‘D‘,500);        map.put(‘M‘,1000);        for (int i = 0; i <schar.length ; i++) {            if (i<schar.length-1) {                //IV                if ((int) map.get(schar[i]) == 1 && (int) map.get(schar[i + 1]) == 5) {                    sum -= 2;                }                //IX                if ((int) map.get(schar[i]) == 1 && (int) map.get(schar[i + 1]) == 10) {                    sum -= 2;                }                //XL                if ((int) map.get(schar[i]) == 10 && (int) map.get(schar[i + 1]) == 50) {                    sum -= 20;                }                //XC                if ((int) map.get(schar[i]) == 10 && (int) map.get(schar[i + 1]) == 100) {                    sum -= 20;                }                //CD                if ((int) map.get(schar[i]) == 100 && (int) map.get(schar[i + 1]) == 500) {                    sum -= 200;                }                //CM                if ((int) map.get(schar[i]) == 100 && (int) map.get(schar[i + 1]) == 1000) {                    sum -= 200;                }            }            sum +=(int) map.get(schar[i]);        }        return  sum;    }}

Submission result:

Leetcode record-convert the number of Rome to an integer