LeetCode

Bitwise AND of Numbers Range

2015.4.17 06:30

Given a range [m, n] where 0 <= m <= n <= 2147483647, return the bitwise AND of all numbers in this range, inclusive.

For example, given the range [5, 7], you should return 4.

Solution:

　　Make it fast and simple.

Accepted code:

// 1AC, easy
class Solution {
public:
    int rangeBitwiseAnd(int m, int n) {
        while (n > m) {
            n = (n & n - 1);
        }
        return m & n;
    }
};