(LeetCode OJ) Power of Two【231】

(LeetCode OJ) Power of Two【231】

231. Power of Two

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Given an integer, write a function to determine if it is a power of two.

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Special thanks to @jianchao.li.fighter for adding this problem and creating all test cases.

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//思路首先：如果一個數是2的某個次方，那麼他一定不會小於等於0（最多無限接近0）
//如果n是2的某個次方，那麼他的二進制形式一定是10000......這樣的形式
//並且n-1的二進制形式一定是01111....，進行與運算一定是false
class Solution {
public:
    bool isPowerOfTwo(int n) {
        if(n <= 0)
            return false;
        if(n&n-1)
            return false;
        else
            return true;
    }
};