LeetCode知识点总结 - 537

LeetCode 537. Complex Number Multiplication

题目

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.

思路

(a + bi) * (c + di) = (ac - bd) + (ad + bc)i

答案

classSolution{publicStringcomplexNumberMultiply(Stringa,Stringb){int[]coefs1=Stream.of(a.split("\\+|i")).mapToInt(Integer::parseInt).toArray(),coefs2=Stream.of(b.split("\\+|i")).mapToInt(Integer::parseInt).toArray();return(coefs1[0]*coefs2[0]-coefs1[1]*coefs2[1])+"+"+(coefs1[0]*coefs2[1]+coefs1[1]*coefs2[0])+"i";}}