LeetCode 201 Bitwise AND of Numbers Range

题目描述

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.

Credits:
Special thanks to @amrsaqr for adding this problem and creating all test cases.

分析

实质：求m和n二进制编码中，相同的前缀

代码

    public static int rangeBitwiseAnd(int m, int n) {

        int bit = 0;

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

        return m << bit;
    }