231. Power of Two

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題目敘述

Given an integer n, return true if it is a power of two. Otherwise, return false.

An integer n is a power of two, if there exists an integer x such that n == 2^x.

Example 1

Input: n = 1 Output: true Explanation: 20 = 1

Example 2

Input: n = 16 Output: true Explanation: 24 = 16

Example 3

Input: n = 3 Output: false

解題思路

Solution

class Solution {
    public boolean isPowerOfTwo(int n) {
        return n > 0 && (n & (n - 1)) == 0;
    }
}