537. Complex Number Multiplication

class Solution:
    def complexNumberMultiply(self, num1: str, num2: str) -> str:
        a, b = map(int, num1[:-1].split('+'))
        c, d = map(int, num2[:-1].split('+'))
        return f'{a * c - b * d}+{a * d + c * b}i'

class Solution {
    public String complexNumberMultiply(String num1, String num2) {
        String[] c1 = num1.split("\\+|i");
        String[] c2 = num2.split("\\+|i");
        int a = Integer.parseInt(c1[0]);
        int b = Integer.parseInt(c1[1]);
        int c = Integer.parseInt(c2[0]);
        int d = Integer.parseInt(c2[1]);
        return String.format("%d+%di", a * c - b * d, a * d + c * b);
    }
}

function complexNumberMultiply(num1: string, num2: string): string {
    let arr1 = num1.split('+'),
        arr2 = num2.split('+');
    let r1 = Number(arr1[0]),
        r2 = Number(arr2[0]);
    let v1 = Number(arr1[1].substring(0, arr1[1].length - 1)),
        v2 = Number(arr2[1].substring(0, arr2[1].length - 1));
    let ansR = r1 * r2 - v1 * v2;
    let ansV = r1 * v2 + r2 * v1;
    return `${ansR}+${ansV}i`;
}

class Solution {
public:
    string complexNumberMultiply(string num1, string num2) {
        int a, b, c, d;
        sscanf(num1.c_str(), "%d+%di", &a, &b);
        sscanf(num2.c_str(), "%d+%di", &c, &d);
        return string(to_string(a * c - b * d) + "+" + to_string(a * d + c * b) + "i");
    }
};

func complexNumberMultiply(num1, num2 string) string {
	parse := func(num string) (a, b int) {
		i := strings.IndexByte(num, '+')
		a, _ = strconv.Atoi(num[:i])
		b, _ = strconv.Atoi(num[i+1 : len(num)-1])
		return
	}
	a, b := parse(num1)
	c, d := parse(num2)
	return fmt.Sprintf("%d+%di", a*c-b*d, a*d+b*c)
}