Question

1611. Minimum One Bit Operations to Make Integers Zero

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Description

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 = 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 2:

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.

 

Constraints:

• 0 <= n <= 109

Solutions

Solution 1

class Solution:
  def minimumOneBitOperations(self, n: int) -> int:
    ans = 0
    while n:
      ans ^= n
      n >>= 1
    return ans

class Solution {
  public int minimumOneBitOperations(int n) {
    int ans = 0;
    for (; n > 0; n >>= 1) {
      ans ^= n;
    }
    return ans;
  }
}

class Solution {
public:
  int minimumOneBitOperations(int n) {
    int ans = 0;
    for (; n > 0; n >>= 1) {
      ans ^= n;
    }
    return ans;
  }
};

func minimumOneBitOperations(n int) (ans int) {
  for ; n > 0; n >>= 1 {
    ans ^= n
  }
  return
}

function minimumOneBitOperations(n: number): number {
  let ans = 0;
  for (; n > 0; n >>= 1) {
    ans ^= n;
  }
  return ans;
}

Solution 2

class Solution:
  def minimumOneBitOperations(self, n: int) -> int:
    if n == 0:
      return 0
    return n ^ self.minimumOneBitOperations(n >> 1)

class Solution {
  public int minimumOneBitOperations(int n) {
    if (n == 0) {
      return 0;
    }
    return n ^ minimumOneBitOperations(n >> 1);
  }
}

class Solution {
public:
  int minimumOneBitOperations(int n) {
    if (n == 0) {
      return 0;
    }
    return n ^ minimumOneBitOperations(n >> 1);
  }
};

func minimumOneBitOperations(n int) int {
  if n == 0 {
    return 0
  }
  return n ^ minimumOneBitOperations(n>>1)
}

function minimumOneBitOperations(n: number): number {
  if (n === 0) {
    return 0;
  }
  return n ^ minimumOneBitOperations(n >> 1);
}