《九日集训》第十三轮（第二讲) 循环

Question

 

 公式法；sizeof(bool[n][n+1])等价于n(n+1)

class Solution {

public:

int sumNums(int n) {

return sizeof(bool[n][n+1])>>1;

}

};

 

 

 

class Solution {public:bool isPowerOfFour(int n) {if(n<=0) return false;int x=(int)(log2(n)/log2(4));if(n-pow(4,x)==0) return true;return

 false;};

3次幂同理 

1. class Solution {

2. public:

3. bool isPowerOfThree(int n) {

4. if(n<=0) return false;

5. int x=(int)(log2(n)/log2(3));

6. if(n-pow(3,x)==0) return true;

7. return false;

8.  

9. }

10. };

 

 

Answer 1

为啥不写在博客里？