13. Roman to Integer

Runtime Error
Line 1240: Char 9: runtime error: addition of unsigned offset to 0x7fd042900140 overflowed to 0x7fd04290013f (basic_string.h)
SUMMARY: UndefinedBehaviorSanitizer: undefined-behavior /usr/bin/../lib/gcc/x86_64-linux-gnu/13/../../../../include/c++/13/bits/basic_string.h:1249:9
Last Executed Input
Open Testcase
s =
"III"

Solution of error : i > 0 &&

class Solution {
public:
    int romanToInt(string s) {
        int sum = 0;
        for (int i = s.length() - 1; i >= 0; i--) {
            switch (s[i]) {
            case 'I':
                if(i> 0 && s[i - 1] == 'V')
                {
                    sum += 6;
                    i--;
                }
                else
                {
                    sum += 1;
                }
                break;

            case 'V':
                if (i > 0 && s[i - 1] == 'I') {
                    sum += 4;
                    i--;
                } else {
                    sum += 5;
                }
                break;

            case 'X':
                if (i > 0 && s[i - 1] == 'I') {
                    sum += 9;
                    i--;
                } else {
                    sum += 10;
                }
                break;

            case 'L':
                if (i > 0 && s[i - 1] == 'X') {
                    sum += 40;
                    i--;
                } else {
                    sum += 50;
                }
                break;

            case 'C':
                if (i > 0 && s[i - 1] == 'X') {
                    sum += 90;
                    i--;
                } else {
                    sum += 100;
                }
                break;

            case 'D':
                if (i > 0 && s[i - 1] == 'C') {
                    sum += 400;
                    i--;
                } else {
                    sum += 500;
                }
                break;

            case 'M':
                if (i > 0 && s[i - 1] == 'C') {
                    sum += 900;
                    i--;
                } else {
                    sum += 1000;
                }
                break;

            default:
                break;
            }
        }
        return sum;
    }
};