题目

Given a positive integer, output its complement number. The complement strategy is to flip the bits of its binary representation.

Note:
The given integer is guaranteed to fit within the range of a 32-bit signed integer.
You could assume no leading zero bit in the integer’s binary representation.
Example 1:
Input: 5
Output: 2
Explanation: The binary representation of 5 is 101 (no leading zero bits), and its complement is 010. So you need to output 2.
Example 2:
Input: 1
Output: 0
Explanation: The binary representation of 1 is 1 (no leading zero bits), and its complement is 0. So you need to output 0.

代码

先用栈存储其二进制最后转换即可,也可用Integer内置方法装换

class Solution {
    public int findComplement(int num) {
        int sum = 0;
        LinkedList<Integer> integers = new LinkedList<>();
        while(num!=0){
            int temp=num%2;
            integers.push(temp);
            num>>>=1;
        }
        Iterator<Integer> iterator = integers.iterator();
        while (iterator.hasNext()){
            Integer next = iterator.next();
            if(next==0)
            {
                sum = sum*2+1;
            }else{
                sum*=2;
            }
        }
        return sum;
    }
}