201. Bitwise AND of Numbers Range

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題目敘述

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

解題思路

Solution

class Solution {
    public int rangeBitwiseAnd(int left, int right) {
        int count = 0;

        while (left < right) {
            left >>= 1;
            right >>= 1;
            count++;
        }

        return left << count;
    }
}