1017. Negative binary conversion

topic：

1017. Negative binary conversion

Thought：

The difference from binary is just not always//2，It’s every number//-1

Code：

class Solution:
    def baseNeg2(self, n: int) -> str:
        k = 1
        ans = []
        while n:
            if n % 2:
                ans.append('1')
                n -= k
            else:
                ans.append('0')
            n //= 2
            k *= -1
        return ''.join(ans[::-1]) or '0' 

impl Solution {
    pub fn base_neg2(mut n: i32) -> String {
        let mut ans = Vec::new();
        while n != 0 {
            if n % 2 != 0 {
                ans.push('1');
                n = (n - 1) / -2;
            } else {
                ans.push('0');
                n /= -2;
            }
        }
        if ans.is_empty() {
            ans.push('0');
        }
        ans.reverse();
        ans.iter().collect()
    }
}