[LeetCode 231] Power of Two

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Description

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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 == 2x.

Example 1

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• Input: n = 1
• Output: true
• Explanation: 2^0 = 1

Example 2

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• Input: n = 16
• Output: true
• Explanation: 2^4 = 16

Example 3

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• Input: n = 3
• Output: false

Constraints

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• -2^31 <= n <= 2^31 - 1

Code

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내 제출

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

Runtime	Memory
0 ms	41.3 MB

다른 풀이

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class Solution {
    public boolean isPowerOfTwo(int n) {
        if(n<=0){
            return false;
        }
        if(n==1){
            return true;
        }
        if(n%2!=0){
            return false;
        }
        else{
            return isPowerOfTwo(n/2);
        }
        
    }
}

Reference

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• https://github.com/doocs/leetcode/blob/main/solution/0200-0299/0231.Power%20of%20Two/Solution.java