[数据结构][Python][经典题目]判断一个数是否为2的整数次幂

深藏阁楼爱情的钟 2022-01-10 03:47 416阅读 0赞

<table> 
 <thead> 
  <tr> 
   <th>十进制</th> 
   <th>二进制</th> 
   <th>是否是2的整数次幂</th> 
  </tr> 
 </thead> 
 <tbody> 
  <tr> 
   <td>8</td> 
   <td>1000B</td> 
   <td>是</td> 
  </tr> 
  <tr> 
   <td>16</td> 
   <td>10000B</td> 
   <td>是</td> 
  </tr> 
  <tr> 
   <td>32</td> 
   <td>100000B</td> 
   <td>是</td> 
  </tr> 
  <tr> 
   <td>64</td> 
   <td>1000000B</td> 
   <td>是</td> 
  </tr> 
  <tr> 
   <td>100</td> 
   <td>1100100B</td> 
   <td>否</td> 
  </tr> 
 </tbody> 
</table>

<table> 
 <thead> 
  <tr> 
   <th>十进制</th> 
   <th>二进制</th> 
   <th>原数值-1</th> 
   <th>是否是2的整数次幂</th> 
  </tr> 
 </thead> 
 <tbody> 
  <tr> 
   <td>8</td> 
   <td>111B</td> 
   <td>是</td> 
   <td></td> 
  </tr> 
  <tr> 
   <td>16</td> 
   <td>11111B</td> 
   <td>是</td> 
   <td></td> 
  </tr> 
  <tr> 
   <td>32</td> 
   <td>11111B</td> 
   <td>是</td> 
   <td></td> 
  </tr> 
  <tr> 
   <td>64</td> 
   <td>111111B</td> 
   <td>是</td> 
   <td></td> 
  </tr> 
  <tr> 
   <td>100</td> 
   <td>1100011B</td> 
   <td>否</td> 
   <td></td> 
  </tr> 
 </tbody> 
</table>

<table> 
 <thead> 
  <tr> 
   <th>十进制</th> 
   <th>二进制</th> 
   <th>原数值-1</th> 
   <th>n&amp;n-1</th> 
   <th>是否是2的整数次幂</th> 
  </tr> 
 </thead> 
 <tbody> 
  <tr> 
   <td>8</td> 
   <td>111B</td> 
   <td>0</td> 
   <td>0</td> 
   <td>是</td> 
  </tr> 
  <tr> 
   <td>16</td> 
   <td>11111B</td> 
   <td>0</td> 
   <td>0</td> 
   <td>是</td> 
  </tr> 
  <tr> 
   <td>32</td> 
   <td>11111B</td> 
   <td>0</td> 
   <td>0</td> 
   <td>是</td> 
  </tr> 
  <tr> 
   <td>64</td> 
   <td>111111B</td> 
   <td>0</td> 
   <td>0</td> 
   <td>是</td> 
  </tr> 
  <tr> 
   <td>100</td> 
   <td>1100011B</td> 
   <td>1100000B</td> 
   <td>1100000B</td> 
   <td>否</td> 
  </tr> 
 </tbody> 
</table>

def power_two(num):
        return num&num-1==0
    if __name__ == '__main__':
        result = power_two(8)
        print(result)