Bitwise AND of Numbers Range LeetCode Solution | Easy Approach

Bitwise AND of Numbers Range Given two integers left and right that represent the range [left, right], return the bitwise AND of all numbers in this range, inclusive.

Example 1:

Input: left = 5, right = 7
Output: 4

Example 2:

Input: left = 0, right = 0
Output: 0

Example 3:

Input: left = 1, right = 2147483647
Output: 0

Constraints:

• 0 <= left <= right <= 231 - 1

Bitwise AND of Numbers Range Solutions

✅Time:O(32)=O(1)
✅Space: O(1)

C++

class Solution {
 public:
  int rangeBitwiseAnd(int m, int n) {
    int shiftBits = 0;

    while (m != n) {
      m >>= 1;
      n >>= 1;
      ++shiftBits;
    }

    return m << shiftBits;
  }
};

Java

 class Solution {
  public int rangeBitwiseAnd(int m, int n) {
    int shiftBits = 0;

    while (m != n) {
      m >>= 1;
      n >>= 1;
      ++shiftBits;
    }

    return m << shiftBits;
  }
}

 

Python

class Solution:
  def rangeBitwiseAnd(self, m: int, n: int) -> int:
    return self.rangeBitwiseAnd(m >> 1, n >> 1) << 1 if m < n else m

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