537. Complex Number

Complex Number Multiplication

A 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.

Constraints:

num1 and num2 are valid complex numbers.

Solution To the Above Question

class Solution {
public:
    int getInt(string num){
        int i=0;
        int number=0;
        bool flag=false;
        if(num[0]=='-'){
            flag=true;
        }
        if(!flag){
        while(num[i]!='+'){
            i++;
        }
            int k=i;
        for(int j=0; j<k; j++){
            number=(num[j]-'0')*pow(10,i-1) +number;
            i--;
        }
        return number;
        }
        if(flag){
            while(num[i]!='+'){
            i++;
        }
            int k=i;
        for(int j=1; j<k; j++){
            number=(num[j]-'0')*pow(10,i-2) +number;
            i--;
        }
        return -1*number;
        }
        return number;
    }
    
    int getInt2(string num){
       int i=0;
        int t=0;
        int n=num.length();
        int number=0;
        while(num[i]!='+'){
            i++;
        }
        while(num[t]!='i'){
            t++;
        }
        bool flag=false;
        if(num[i+1]=='-'){
            flag=true;
        }
        if(!flag){
        
            int k=t-i;
        for(int j=i+1; j<n-1; j++){
            number=(num[j]-'0')*pow(10,k-2) +number;
            k--;
        }
        return number;
        }
        if(flag){
            
            int k=t-i-1;
        for(int j=i+2; j<n-1; j++){
            number=(num[j]-'0')*pow(10,k-2) +number;
            k--;
        }
        return -1*number;
        }
        return number;
    }
    
    
    string complexNumberMultiply(string num1, string num2) {
        int r1=getInt(num1);
        int i1=getInt2(num1);
        int r2=getInt(num2);
        int i2=getInt2(num2);
        cout<<r1<<" "<<r2<<" "<<i1<<" "<<i2;
        int ans1=r1*r2-i1*i2;
        int ans2=r1*i2+r2*i1;
        
       string answer="";
        answer=to_string(ans1)+'+'+ to_string(ans2)+'i';
        
        return answer;
    }
};