README.md

537. Complex Number Multiplication

Given two strings representing two complex numbers.

You need to return a string representing their multiplication. Note i² = -1 according to the definition.

Example 1:

Input: "1+1i", "1+1i"
Output: "0+2i"
Explanation: (1 + i) * (1 + i) = 1 + i2 + 2 * i = 2i, and you need convert it to the form of 0+2i.

Example 2:

Input: "1+-1i", "1+-1i"
Output: "0+-2i"
Explanation: (1 - i) * (1 - i) = 1 + i2 - 2 * i = -2i, and you need convert it to the form of 0+-2i.

Note:

1. The input strings will not have extra blank.
2. The input strings will be given in the form of a+bi, where the integer a and b will both belong to the range of [-100, 100]. And the output should be also in this form.

Solutions (Python)

1. Solution

class Solution:
    def complexNumberMultiply(self, a: str, b: str) -> str:
        a = [int(x) for x in a[:-1].split('+')]
        b = [int(x) for x in b[:-1].split('+')]

        c = a[0] * b[0] - a[1] * b[1]
        d = a[0] * b[1] + a[1] * b[0]

        return "%d+%di" % (c, d)