struct Solution {}
impl Solution {
    pub fn find_complement(num: i32) -> i32 {
        let zeros = num.leading_zeros();
        println!("zeros={}", zeros);
        let ones = 32 - zeros;
        let mut s = 0;
        let mut i = 0;
        while i < ones {
            s |= 1 << i;
            i += 1;
        }
        let mut num = !num;
        num &= s;
        num
    }
}
#[cfg(test)]
mod test {
    use super::*;

    #[test]
    fn test() {
        assert_eq!(Solution::find_complement(3), 0);
        assert_eq!(Solution::find_complement(5), 2);
        assert_eq!(Solution::find_complement(-1), 0);
    }
}