[leedcode 231] Power of Two
Given an integer, write a function to determine if it is a power of two.
public class Solution { //注意0和负数都返回false!!! /*public boolean isPowerOfTwo(int n) { if(n<=0) return false;//此方法关键是使用Integer.toBinaryString(n),将整数转化为二进制的字符串 String m=Integer.toBinaryString(n); for(int i=1;i<m.length();i++){ if(m.charAt(i)=='1') return false; } return true; }*/ /* public boolean isPowerOfTwo(int n) { if(n<=0) return false; while(n>0){ if(n!=1&&n%2==1) return false; n=n>>1; } return true; }*/ public boolean isPowerOfTwo(int n) { if(n<=0) return false; return (n&(n-1))==0; } }