2595. Number of Even and Odd Bits
Description
You are given a positive integer n
.
Let even
denote the number of even indices in the binary representation of n
with value 1.
Let odd
denote the number of odd indices in the binary representation of n
with value 1.
Note that bits are indexed from right to left in the binary representation of a number.
Return the array [even, odd]
.
Example 1:
Input: n = 50
Output: [1,2]
Explanation:
The binary representation of 50 is 110010
.
It contains 1 on indices 1, 4, and 5.
Example 2:
Input: n = 2
Output: [0,1]
Explanation:
The binary representation of 2 is 10
.
It contains 1 only on index 1.
Constraints:
1 <= n <= 1000
Solutions
Solution 1: Enumerate
According to the problem description, enumerate the binary representation of $n$ from the low bit to the high bit. If the bit is $1$, add $1$ to the corresponding counter according to whether the index of the bit is odd or even.
The time complexity is $O(\log n)$ and the space complexity is $O(1)$. Where $n$ is the given integer.
1 2 3 4 5 6 7 8 9 |
|
1 2 3 4 5 6 7 8 9 |
|
1 2 3 4 5 6 7 8 9 10 |
|
1 2 3 4 5 6 7 |
|
1 2 3 4 5 6 7 |
|
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 |
|
Solution 2
1 2 3 4 5 6 |
|
1 2 3 4 5 6 7 8 |
|
1 2 3 4 5 6 7 8 9 |
|
1 2 3 4 5 6 |
|
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 |
|
1 2 3 4 5 6 7 8 |
|