# Complex Number Multiplication LeetCode Solution

Here, We see Complex Number Multiplication LeetCode Solution. This Leetcode problem is done in many programming languages like C++, Java, JavaScript, Python, etc. with different approaches.

# List of all LeetCode Solution

## Problem Statement

complex number can be represented as a string on the form `"real+imaginaryi"` where:

• `real` is the real part and is an integer in the range `[-100, 100]`.
• `imaginary` is the imaginary part and is an integer in the range `[-100, 100]`.
• `i2 == -1`.

Given two complex numbers `num1` and `num2` as strings, return a string of the complex number that represents their multiplications.

Example 1:
Input: num1 = “1+1i”, num2 = “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: num1 = “1+-1i”, num2 = “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.

## Complex Number Multiplication LeetCode SolutionC++

``````class Solution {
public:
string complexNumberMultiply(string num1, string num2) {
string res = "" ;
int a1 = real(num1) ;
int a2 = real(num2) ;
int b1 = complex(num1) ;
int b2 = complex(num2) ;
res = res + to_string(a1*a2-b1*b2)+'+'+to_string(a1*b2+a2*b1)+'i' ;
return res ;
}

int real(string str){
int i = 0 ;
string real = "" ;
while(str[i]!='+'){
real += str[i] ;
i++ ;
}
return stoi(real) ;
}

int complex(string str){
int i = 0 ;
string complex = "" ;
while(str[i]!='+'){
i++ ;
}
i++ ;
while(str[i]!='i'){
complex += str[i] ;
i++ ;
}
return stoi(complex) ;
}
};```Code language: PHP (php)```

## Complex Number Multiplication SolutionJava

``````class Solution {
public String complexNumberMultiply(String num1, String num2) {
String[] a = num1.split("\\+|i");
String[] b = num2.split("\\+|i");
int ar = Integer.parseInt(a[0]), ai = Integer.parseInt(a[1]);
int br = Integer.parseInt(b[0]), bi = Integer.parseInt(b[1]);
return String.format("%d+%di",ar*br -ai*bi, ar*bi + ai*br);
}
}```Code language: JavaScript (javascript)```

## Complex Number Multiplication SolutionJavaScript

``````var complexNumberMultiply = function(num1, num2) {
var a = parseInt(num1.split("+")[0]);
var b = parseInt(num1.split("+")[1].replace("i", ""));
var c = parseInt(num2.split("+")[0]);
var d = parseInt(num2.split("+")[1].replace("i", ""));
return `\${a * c - b * d}+\${a * d + b * c}i`;
};```Code language: JavaScript (javascript)```

## Complex Number Multiplication SolutionPython

``````class Solution(object):
def complexNumberMultiply(self, num1, num2):
a, b = int(num1[:num1.index("+")]), int(num1[num1.index("+")+1:-1])
c, d = int(num2[:num2.index("+")]), int(num2[num2.index("+")+1:-1])
real_part = a * c - b * d
imag_part = a * d + b * c
result = str(real_part) + "+" + str(imag_part) + "i"
return result``````
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