231.power-of-two.java

/*
 * @lc app=leetcode id=231 lang=java
 *
 * [231] Power of Two
 *
 * https://leetcode.com/problems/power-of-two/description/
 *
 * algorithms
 * Easy (41.58%)
 * Total Accepted:    211.8K
 * Total Submissions: 509.3K
 * Testcase Example:  '1'
 *
 * Given an integer, write a function to determine if it is a power of two.
 *
 * Example 1:
 *
 *
 * Input: 1
 * Output: true
 * Explanation: 20 = 1
 *
 *
 * Example 2:
 *
 *
 * Input: 16
 * Output: true
 * Explanation: 24 = 16
 *
 * Example 3:
 *
 *
 * Input: 218
 * Output: false
 *
 */
class Solution {
  public boolean isPowerOfTwo(int n) {
    if (n <= 0) return false;
    if ((n & (n-1)) == 0) {
      return true;
    }
    return false;
  }
}