Leetcode——537. Complex Number Multiplication

题目原址

https://leetcode.com/problems/complex-number-multiplication/description/

题目描述

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.

解题思路

给定两个复数，求两个复数相×的结果。。这个题主要就是考察将给定的字符串按照指定符号分割

AC代码

class Solution {public String complexNumberMultiply(String a, String b) {String[] i1 = a.split("\\+");String[] ii1 = a.split("\\+")[1].split("i");String[] i2 = b.split("\\+");String[] ii2 = b.split("\\+")[1].split("i");int eqq1 = Integer.parseInt(i1[0]) * Integer.parseInt(i2[0]);int eqq2 = Integer.parseInt(i1[0]) * Integer.parseInt(ii2[0]);int eqq3 = Integer.parseInt(ii1[0]) * Integer.parseInt(i2[0]);int eqq4 = Integer.parseInt(ii1[0]) * Integer.parseInt(ii2[0]);int sum = eqq1 - eqq4;int e = eqq2 + eqq3;StringBuilder sb = new StringBuilder();sb.append(sum);sb.append('+');sb.append(e);sb.append("i");return sb.toString();}
}