Leetcode 201. Bitwise AND of Num

文章作者：Tyan
博客：noahsnail.com  |  CSDN  |  简书

1. Description

Bitwise AND of Numbers Range

2. Solution

• Version 1

class Solution {
public:
    int rangeBitwiseAnd(int m, int n) {
        int mask = INT_MAX;
        while((m & mask) != (n & mask)) {
            mask <<= 1;
        }
        return m & mask;
    }
};

• Version 2

class Solution {
public:
    int rangeBitwiseAnd(int m, int n) {
        int count = 0;
        while(m != n) {
            m >>= 1;
            n >>= 1;
            count++;
        }
        return m << count;
    }
};

• Version 3

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

Reference

1. https://leetcode.com/problems/bitwise-and-of-numbers-range/description/