leetcode

0 class Solution {

1 public:

2 string fractionAddition(const string &expression) const {

3 const int n = size(expression);

4 int numerator = 0, denominator = 1;

5

6 for (int i = 0; i < n;) {

7 int sign = 1;

8 if (expression[i] == '+' || expression[i] == '-') {

9 if (expression[i] == '-') sign = -1;

10 i++;

11 }

12

13 int num = 0;

14 while (i < n && isdigit(expression[i])) {

15 num = num * 10 + (expression[i] - '0');

16 i++;

17 }

18 num *= sign;

19

20 i++;

21

22 int den = 0;

23 while (i < n && isdigit(expression[i])) {

24 den = den * 10 + (expression[i] - '0');

25 i++;

26 }

27

28 numerator = numerator * den + num * denominator;

29 denominator *= den;

30

31 int gcdVal = gcd(abs(numerator), denominator);

32 numerator /= gcdVal;

33 denominator /= gcdVal;

34 }

35

36 return to_string(numerator) + "/" + to_string(denominator);

37 }

38 };