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]. And the output should be also in this form.
A:
就是个实现题
class Solution { public: string complexNumberMultiply(string a, string b) { auto va = getComplex(a); auto vb = getComplex(b); int c1 = va[0], i1 = va[1]; int c2 = vb[0], i2 = vb[1]; int resC = c1*c2 - i1*i2; int resI = c1*i2 + c2*i1; return to_string(resC) + "+"+to_string(resI) + "i"; } private: vector<int> getComplex(string str){ if(str[0]=='+') str = str.substr(1); int n = str.length(); int plusIndex = str.find('+'); int a = stoi(str.substr(0,plusIndex)); int b = stoi(str.substr(plusIndex+1, str.length() -2-plusIndex )); return vector<int>{a,b}; } };
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