537. Complex Number Multiplication

简单题，由于输入格式固定，所以求解简单

class Solution {
public:


    vector<string> split(string s){

        vector<string> result;
        int start = 0;
        int end = 0;
        while(s[end]!='+')
            end++;

        result.push_back(s.substr(start, end-start));

        end = end+1;
        start = end;

        while(s[end]!='i')
            end++;

        result.push_back(s.substr(start, end-start));

        return result;
    }

    string complexNumberMultiply(string a, string b) {

        vector<string> split_a = split(a);
        vector<string> split_b = split(b);

        cout<<split_a[0]<<" "<<split_a[1]<<endl;
        cout<<split_b[0]<<" "<<split_b[1]<<endl;

        int real = atoi(split_a[0].c_str())*atoi(split_b[0].c_str()) -  atoi(split_a[1].c_str())*atoi(split_b[1].c_str());

        int complex = atoi(split_a[0].c_str())*atoi(split_b[1].c_str()) + atoi(split_a[1].c_str())*atoi(split_b[0].c_str());

        string result = to_string(real) + "+" + to_string(complex) + "i";

        return result;
    }
};