문제
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.
풀이
주어진 문자열에서 기호 다빼고 숫자만 저장한다음에 곱셈을 하고 다시 기호나 i를 붙여주면 된다.
/**
* @param {string} a
* @param {string} b
* @return {string}
*/
const getArray = str => {
// 1+-1i
const array = [];
let temp = "";
for (let i = 0; i < str.length; i++) {
if (str[i] === "+" || str[i] === "i") {
array.push(temp);
temp = "";
} else if (str[i] === "-") {
temp += str[++i] * -1;
} else {
temp += str[i];
}
}
return array;
};
var complexNumberMultiply = function(a, b) {
const arr1 = getArray(a); // 1, -1
const arr2 = getArray(b); // 1, -1
const resultArr = [arr1[0] * arr2[0], arr1[0] * arr2[1], arr1[1] * arr2[0], arr1[1] * arr2[1]];
const subStr = resultArr[1] + resultArr[2] + "i";
const sum = resultArr[0] + resultArr[3] * -1;
const resultStr = sum.toString() + "+" + subStr;
return resultStr;
};결과
출처
https://leetcode.com/problems/complex-number-multiplication/