Every non-negative integer N
has a binary representation. For example, 5
can be represented as "101"
in binary, 11
as "1011"
in binary, and so on. Note that except for N = 0
, there are no leading zeroes in any binary representation.
The complement of a binary representation is the number in binary you get when changing every 1
to a 0
and 0
to a 1
. For example, the complement of "101"
in binary is "010"
in binary.
For a given number N
in base-10, return the complement of it's binary representation as a base-10 integer.
Example 1:
Input: 5 Output: 2 Explanation: 5 is "101" in binary, with complement "010" in binary, which is 2 in base-10.
Example 2:
Input: 7 Output: 0 Explanation: 7 is "111" in binary, with complement "000" in binary, which is 0 in base-10.
Example 3:
Input: 10 Output: 5 Explanation: 10 is "1010" in binary, with complement "0101" in binary, which is 5 in base-10.
Note:
0 <= N < 10^9
Companies:
Cloudera
Related Topics:
Math
// OJ: https://leetcode.com/problems/complement-of-base-10-integer/
// Author: github.com/lzl124631x
// Time: O(1)
// Space: O(1)
class Solution {
public:
int bitwiseComplement(int N) {
if (!N) return 1;
unsigned mask = ~0;
while (mask & N) mask <<= 1;
return ~N & ~mask;
}
};