bitwise_and_of_numbers_range.dart

/*


-* 201 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

*/

class Solution {
  int rangeBitwiseAnd(int left, int right) {
    int shiftCount = 0;
    while (left < right) {
      left >>= 1;
      right >>= 1;
      shiftCount += 1;
    }
    return left << shiftCount;
  }
  int rangeBitwiseAnd2(int left, int right) {
     while (right > left) {
      right &= (right - 1);
    }
    return right;
  }
}