Power of two
1 min read

Power of two

Power of two

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

Example 1:

Input: 1
Output: true 
Explanation: 2 pow 0 = 1

Example 2:

Input: 16
Output: true
Explanation: 2 pow 4 = 16

Example 3:

Input: 218
Output: false

Solution

If a number is power of 2, then its high bit is 1 and there is only one 1. Therefore, number & (number-1) is 0.

fun isPowerofTwo(n: Int): Boolean {
    return (n>0).and((n and (n-1)) == 0)
}

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