[Leetcode] #537 Complex Number Multiplication(stringstream)

Discription

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.

Solution

#include <sstream>

string complexNumberMultiply(string a, string b) {
    int ra, ia, rb, ib;
    char buff;
    stringstream aa(a), bb(b), ans;
    aa >> ra >> buff >> ia >> buff;
    bb >> rb >> buff >> ib >> buff;
    ans << ra*rb - ia*ib << "+" << ra*ib + rb*ia << "i";
    return ans.str();
}

GitHub-Leetcode:https://github.com/wenwu313/LeetCode