231. Power of Two
Topic Bit Manipulation
Area Algorithms
Summary
if n is power of 2, in binary it will look like 0001000...0 then, if you do n-1, it will look like 00001111...1 then, if you take & operator to them, it will al
Problem
Difficulty: Easy
Tags: Math, Bit Manipulation, Recursion
Intuition
i knew I have to deal with bits in this problem, but i couldn’t figure out how. and the discussion give me a hint.
Approach
if n is power of 2, in binary it will look like 0001000…0 then, if you do n-1, it will look like 00001111…1 then, if you take & operator to them, it will always get 00000…0, which is 0.
Solution
bool isPowerOfTwo(int n) {
if (n <= 0){
return false;
}
return !(n & (n-1));
}Complexity
-
Time:
-
Space: