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:
- The input strings will not have extra blank.
- 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]. Andthe output should be also in this form.
1 class Solution { 2 public: 3 int str2num(string s) 4 { 5 int num; 6 stringstream ss(s); 7 ss >> num; 8 return num; 9 } 10 string num2str(double i) 11 { 12 stringstream ss; 13 ss << i; 14 return ss.str(); 15 } 16 string complexNumberMultiply(string a, string b) { 17 int alen = a.size(); 18 int blen = b.size(); 19 string a1 = "", a2 = "", b1 = "", b2 = ""; 20 int aj = 0; int i; 21 for (i = 0; i < alen; i++) 22 { 23 if (a[i] == '+') 24 aj = i; 25 } 26 int bj = 0; int j; 27 for (j = 0; j < blen; j++) 28 { 29 if (b[j] == '+') 30 bj = j; 31 } 32 a1 = a.substr(0, aj); 33 a2 = a.substr(aj + 1, alen - aj - 1); 34 b1 = b.substr(0, bj); 35 b2 = b.substr(bj + 1, blen - bj - 1); 36 int A1 = str2num(a1); 37 int A2 = str2num(a2); 38 int B1 = str2num(b1); 39 int B2 = str2num(b2); 40 int first = A1*B1 - A2*B2; 41 int second = A1*B2 + A2*B1; 42 return num2str(first) + "+" + num2str(second) + "i"; 43 } 44 };
1 class Solution { 2 public: 3 string complexNumberMultiply(string a, string b) { 4 int alen = a.size(); 5 int blen = b.size(); 6 string a1 = "", a2 = "", b1 = "", b2 = ""; 7 int aj =a.find('+'); 8 int bj = b.find('+'); 9 a1 = a.substr(0, aj); 10 a2 = a.substr(aj + 1, alen - aj - 1); 11 b1 = b.substr(0, bj); 12 b2 = b.substr(bj + 1, blen - bj - 1); 13 int A1 = stoi(a1); 14 int A2 = stoi(a2); 15 int B1 = stoi(b1); 16 int B2 = stoi(b2); 17 int first = A1*B1 - A2*B2; 18 int second = A1*B2 + A2*B1; 19 return to_string(first) + "+" + to_string(second) + "i"; 20 } 21 };
