LeetCode -- 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.
就是对从m到n之间的数字做与运算。
思路:
本题的关键在于,求出了n& n-1为v,就可以直接把n设为v,而没必要在求v与n-1之间的数了。
实现代码:
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.
就是对从m到n之间的数字做与运算。
思路:
本题的关键在于,求出了n& n-1为v,就可以直接把n设为v,而没必要在求v与n-1之间的数了。
实现代码:
public class Solution {
public int RangeBitwiseAnd(int m, int n)
{
while(n > m){
n = n & n-1;
}
return n & m ;
}
}