1611. Minimum One Bit Operations to Make Integers Zero

Given an integer `n`, you must transform it into `0` using the following operations any number of times:

• Change the rightmost (`0th`) bit in the binary representation of `n`.
• Change the `ith` bit in the binary representation of `n` if the `(i-1)th` bit is set to `1` and the `(i-2)th` through `0th` bits are set to `0`.

Return the minimum number of operations to transform `n` into `0`.

Example 1:

```Input: n = 0
Output: 0
```

Example 2:

```Input: n = 3
Output: 2
Explanation: The binary representation of 3 is "11".
"11" -> "01" with the 2nd operation since the 0th bit is 1.
"01" -> "00" with the 1st operation.
```

Example 3:

```Input: n = 6
Output: 4
Explanation: The binary representation of 6 is "110".
"110" -> "010" with the 2nd operation since the 1st bit is 1 and 0th through 0th bits are 0.
"010" -> "011" with the 1st operation.
"011" -> "001" with the 2nd operation since the 0th bit is 1.
"001" -> "000" with the 1st operation.
```

Example 4:

```Input: n = 9
Output: 14
```

Example 5:

```Input: n = 333
Output: 393
```

Constraints:

• `0 <= n <= 109`

1611. Minimum One Bit Operations to Make Integers Zero
``````struct Solution;

impl Solution {
fn minimum_one_bit_operations(n: i32) -> i32 {
if n <= 1 {
n
} else {
let mut bit = 0;
while 1 << bit <= n {
bit += 1;
}
let m = n ^ (1 << (bit - 1));
let k = (1 << bit) - 1;
k - Solution::minimum_one_bit_operations(m)
}
}
}

#[test]
fn test() {
let n = 0;
let res = 0;
assert_eq!(Solution::minimum_one_bit_operations(n), res);
let n = 3;
let res = 2;
assert_eq!(Solution::minimum_one_bit_operations(n), res);
let n = 6;
let res = 4;
assert_eq!(Solution::minimum_one_bit_operations(n), res);
}
``````