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.
每一位^1可得该位的反码。构造一个a= 100..., a-1=111.., 与原num抑或。
class Solution {
public int findComplement(int num) {
int a = 1; int ori = num;
while(num > 0){
num = num>>1;
a = a<<1;
}
return (a-1)^ori;
}
}
