LeetCode-Go/website/content/ChapterFour/1017.Convert-to-Base--2.md

1017. Convert to Base -2

题目

Given a number N, return a string consisting of "0"s and "1"s that represents its value in base -2 (negative two).

The returned string must have no leading zeroes, unless the string is "0".

Example 1:

Input: 2
Output: "110"
Explantion: (-2) ^ 2 + (-2) ^ 1 = 2

Example 2:

Input: 3
Output: "111"
Explantion: (-2) ^ 2 + (-2) ^ 1 + (-2) ^ 0 = 3

Example 3:

Input: 4
Output: "100"
Explantion: (-2) ^ 2 = 4

Note:

1. 0 <= N <= 10^9

题目大意

给出数字 N，返回由若干 "0" 和 "1"组成的字符串，该字符串为 N 的负二进制（base -2）表示。除非字符串就是 "0"，否则返回的字符串中不能含有前导零。

提示：

• 0 <= N <= 10^9

解题思路

• 给出一个十进制的数，要求转换成 -2 进制的数
• 这一题仿造十进制转二进制的思路，短除法即可。

代码

package leetcode

import "strconv"

func baseNeg2(N int) string {
	if N == 0 {
		return "0"
	}
	res := ""
	for N != 0 {
		remainder := N % (-2)
		N = N / (-2)
		if remainder < 0 {
			remainder += 2
			N++
		}
		res = strconv.Itoa(remainder) + res
	}
	return res
}