1009. Complement of Base 10 Integer
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
- This question is the same as 476: https://leetcode.com/problems/number-complement/
Rust Solution
struct Solution;
impl Solution {
fn bitwise_complement(n: i32) -> i32 {
if n == 0 {
return 1;
}
let mut mask = !0;
while mask & n != 0 {
mask <<= 1;
}
mask = !mask;
mask ^ n
}
}
#[test]
fn test() {
assert_eq!(Solution::bitwise_complement(5), 2);
assert_eq!(Solution::bitwise_complement(7), 0);
assert_eq!(Solution::bitwise_complement(10), 5);
assert_eq!(Solution::bitwise_complement(0), 1);
}
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