# 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:

Example 2:

Example 3:

# 思路

![]( http://latex.codecogs.com/gif.latex?d \equiv d - N \left \textrm{mod}\ N \right N < 0, d < 0, d+N > 0)