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/*

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

*/

/*

inclusive means including left and right 包括左和右

[26 30]

26 11 010

27 11 011

28 11 100

29 11 101

30 11 110

规律就是找到左边公共部分 - 公共部分是 1 的部分

那么就是left和right共同右移，记下右移的次数，直到left和right相等。然后再将此时的left左移移动次数。

*/

class Solution {

public:

int rangeBitwiseAnd(int left, int right) {

int count = 0;

while(left != right) {

left >>= 1;

right >>= 1;

count++;

}

return left << count;

}

};