326. Power of Three【E】【81】

本文提供了一个Python函数,用于确定给定整数是否是3的幂次。该函数采用递归方法实现,并提供了不使用循环或递归的解决方案。通过找到32位最大的3的幂来优化计算过程。


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

Follow up:
Could you do it without using any loop / recursion?

Credits:
Special thanks to @dietpepsi for adding this problem and creating all test cases.


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class Solution(object):
    def isPowerOfThree(self, n):
        if n == 0:
            return False
        if n == 1:
            return True
        if n % 3 != 0:
            return False
        return self.isPowerOfThree(n/3)
        
        
        '''这个方法就比较流氓了,找到32位最大的3的幂
        if n <= 0:
            return False
        else:
            return 1162261467 % n == 0
        '''
        
        #while n > 0:
            
        
        
        """
        :type n: int
        :rtype: bool
        """
        


[root@yfw ~]# cd /opt/openfire/enterprise/spark/Spark [root@yfw Spark]# # 推荐使用 openfire 用户身份运行(更安全) [root@yfw Spark]# su - openfire -s /bin/bash ✅ JAVA_HOME: /usr/lib/jvm/java-11-openjdk ✅ Maven home: /opt/maven ✅ Java version: openjdk version "11.0.13" 2021-10-19 LTS [openfire@yfw ~]$ [openfire@yfw ~]$ # 切换到 Spark 目录 [openfire@yfw ~]$ cd /opt/openfire/enterprise/spark/Spark [openfire@yfw Spark]$ [openfire@yfw Spark]$ # 设置 DISPLAY 环境变量(通常为 :0) [openfire@yfw Spark]$ export DISPLAY=:0 [openfire@yfw Spark]$ [openfire@yfw Spark]$ # 启动 Spark [openfire@yfw Spark]$ ./Spark ./Spark: line 384: basename: command not found ./Spark: line 385: dirname: command not found ./Spark: line 400: dirname: command not found ./Spark: line 401: basename: command not found ./Spark: line 81: expr: command not found ./Spark: line 82: expr: command not found ./Spark: line 96: awk: command not found ./Spark: line 97: cp: command not found ./Spark: line 100: sed: command not found ./Spark: line 103: chmod: command not found ./Spark: line 172: expr: command not found ./Spark: line 172: [: -eq: unary operator expected ./Spark: line 172: expr: command not found ./Spark: line 172: [: -eq: unary operator expected ./Spark: line 172: expr: command not found ./Spark: line 172: [: -eq: unary operator expected ./Spark: line 172: expr: command not found ./Spark: line 172: [: -eq: unary operator expected ./Spark: line 172: expr: command not found ./Spark: line 172: [: -eq: unary operator expected Error: Could not find or load main class install4j.org.jivesoftware.launcher.Startup [openfire@yfw Spark]$ echo $PATH /usr/local/ffmpeg/bin:/opt/spark/bin:=en_US.UTF-8:/usr/local/ffmpeg/bin [openfire@yfw Spark]$ export PATH="/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin" [openfire@yfw Spark]$ ls /usr/bin | grep -E "(cp|sed|basename|dirname)" basename cp cpack cpack3 cpan cpan-mirrors cpio cpp cpupower dirname lscpu mcpp rpm2cpio scp sed sedismod sedispol tcptraceroute [openfire@yfw Spark]$ which cp # 应该输出 /usr/bin/cp /usr/bin/cp [openfire@yfw Spark]$ which sed # /usr/bin/sed /usr/bin/sed [openfire@yfw Spark]$ which java # 可能是 /usr/lib/jvm/java-11-openjdk/bin/java /usr/bin/java [openfire@yfw Spark]$ java -version # 查看 Java 版本 openjdk version "1.8.0_312" OpenJDK Runtime Environment (build 1.8.0_312-b07) OpenJDK 64-Bit Server VM (build 25.312-b07, mixed mode) [openfire@yfw Spark]$ ls /usr/lib/jvm/java-11-openjdk/ bin conf include legal lib release tapset [openfire@yfw Spark]$ /usr/lib/jvm/java-11-openjdk/bin/java -version openjdk version "11.0.13" 2021-10-19 LTS OpenJDK Runtime Environment 18.9 (build 11.0.13+8-LTS) OpenJDK 64-Bit Server VM 18.9 (build 11.0.13+8-LTS, mixed mode, sharing) [openfire@yfw Spark]$ export JAVA_HOME=/usr/lib/jvm/java-11-openjdk [openfire@yfw Spark]$ export PATH=$JAVA_HOME/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin [openfire@yfw Spark]$ java -version openjdk version "11.0.13" 2021-10-19 LTS OpenJDK Runtime Environment 18.9 (build 11.0.13+8-LTS) OpenJDK 64-Bit Server VM 18.9 (build 11.0.13+8-LTS, mixed mode, sharing) [openfire@yfw Spark]$ cd /opt/openfire/enterprise/spark/Spark [openfire@yfw Spark]$ ./Spark java.lang.reflect.InvocationTargetException at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.base/java.lang.reflect.Method.invoke(Method.java:566) at org.jivesoftware.launcher.Startup.start(Startup.java:75) at org.jivesoftware.launcher.Startup.main(Startup.java:31) at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.base/java.lang.reflect.Method.invoke(Method.java:566) at com.exe4j.runtime.LauncherEngine.launch(LauncherEngine.java:84) at com.install4j.runtime.launcher.UnixLauncher.start(UnixLauncher.java:69) at install4j.org.jivesoftware.launcher.Startup.main(Unknown Source) Caused by: java.awt.AWTError: Can't connect to X11 window server using ':0' as the value of the DISPLAY variable. at java.desktop/sun.awt.X11GraphicsEnvironment.initDisplay(Native Method) at java.desktop/sun.awt.X11GraphicsEnvironment$1.run(X11GraphicsEnvironment.java:102) at java.base/java.security.AccessController.doPrivileged(Native Method) at java.desktop/sun.awt.X11GraphicsEnvironment.<clinit>(X11GraphicsEnvironment.java:61) at java.base/java.lang.Class.forName0(Native Method) at java.base/java.lang.Class.forName(Class.java:315) at java.desktop/java.awt.GraphicsEnvironment$LocalGE.createGE(GraphicsEnvironment.java:101) at java.desktop/java.awt.GraphicsEnvironment$LocalGE.<clinit>(GraphicsEnvironment.java:83) at java.desktop/java.awt.GraphicsEnvironment.getLocalGraphicsEnvironment(GraphicsEnvironment.java:129) at java.desktop/sun.awt.X11.XToolkit.<clinit>(XToolkit.java:231) at java.base/java.lang.Class.forName0(Native Method) at java.base/java.lang.Class.forName(Class.java:315) at java.desktop/java.awt.Toolkit$2.run(Toolkit.java:588) at java.desktop/java.awt.Toolkit$2.run(Toolkit.java:583) at java.base/java.security.AccessController.doPrivileged(Native Method) at java.desktop/java.awt.Toolkit.getDefaultToolkit(Toolkit.java:582) at java.desktop/sun.swing.SwingUtilities2.getSystemMnemonicKeyMask(SwingUtilities2.java:2212) at java.desktop/javax.swing.plaf.basic.BasicLookAndFeel.initComponentDefaults(BasicLookAndFeel.java:1096) at java.desktop/javax.swing.plaf.metal.MetalLookAndFeel.initComponentDefaults(MetalLookAndFeel.java:440) at java.desktop/javax.swing.plaf.basic.BasicLookAndFeel.getDefaults(BasicLookAndFeel.java:150) at java.desktop/javax.swing.plaf.metal.MetalLookAndFeel.getDefaults(MetalLookAndFeel.java:1560) at java.desktop/javax.swing.UIManager.setLookAndFeel(UIManager.java:587) at java.desktop/javax.swing.UIManager.setLookAndFeel(UIManager.java:629) at java.desktop/javax.swing.UIManager.initializeDefaultLAF(UIManager.java:1404) at java.desktop/javax.swing.UIManager.initialize(UIManager.java:1517) at java.desktop/javax.swing.UIManager.maybeInitialize(UIManager.java:1483) at java.desktop/javax.swing.UIManager.getInstalledLookAndFeels(UIManager.java:422) at java.desktop/javax.swing.UIManager.installLookAndFeel(UIManager.java:465) at java.desktop/javax.swing.UIManager.installLookAndFeel(UIManager.java:484) at org.jivesoftware.spark.ui.themes.LookAndFeelManager.<clinit>(LookAndFeelManager.java:40) at org.jivesoftware.Spark.startup(Spark.java:163) ... 13 more [openfire@yfw Spark]$ xhost +si:localuser:openfire xhost: unable to open display ":0" [openfire@yfw Spark]$ export JAVA_HOME=/usr/lib/jvm/java-11-openjdk [openfire@yfw Spark]$ export PATH=$JAVA_HOME/bin:$PATH [openfire@yfw Spark]$ [openfire@yfw Spark]$ cd /opt/openfire/enterprise/spark/Spark [openfire@yfw Spark]$ [openfire@yfw Spark]$ java \ > -Djava.awt.headless=true \ > -cp "lib/*" \ > org.jivesoftware.launcher.Startup Warning: no working directory set. This might cause updated data to be missed. Please set a system property 'appdir' to the location where Spark is installed to correct this. java.lang.reflect.InvocationTargetException at java.desktop/java.awt.EventQueue.invokeAndWait(EventQueue.java:1367) at java.desktop/java.awt.EventQueue.invokeAndWait(EventQueue.java:1342) at org.jivesoftware.Spark.startup(Spark.java:186) at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.base/java.lang.reflect.Method.invoke(Method.java:566) at org.jivesoftware.launcher.Startup.start(Startup.java:75) at org.jivesoftware.launcher.Startup.main(Startup.java:31) Caused by: java.awt.HeadlessException at java.desktop/java.awt.GraphicsEnvironment.checkHeadless(GraphicsEnvironment.java:208) at java.desktop/java.awt.Window.<init>(Window.java:548) at java.desktop/java.awt.Frame.<init>(Frame.java:423) at java.desktop/java.awt.Frame.<init>(Frame.java:388) at java.desktop/javax.swing.JFrame.<init>(JFrame.java:180) at org.jivesoftware.Spark.lambda$startup$0(Spark.java:188) at java.desktop/java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:303) at java.desktop/java.awt.EventQueue.dispatchEventImpl(EventQueue.java:770) at java.desktop/java.awt.EventQueue$4.run(EventQueue.java:721) at java.desktop/java.awt.EventQueue$4.run(EventQueue.java:715) at java.base/java.security.AccessController.doPrivileged(Native Method) at java.base/java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:85) at java.desktop/java.awt.EventQueue.dispatchEvent(EventQueue.java:740) at java.desktop/java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:203) at java.desktop/java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:124) at java.desktop/java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:113) at java.desktop/java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:109) at java.desktop/java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:101) at java.desktop/java.awt.EventDispatchThread.run(EventDispatchThread.java:90) [openfire@yfw Spark]$ sudo yum install xorg-x11-server-Xvfb -y We trust you have received the usual lecture from the local System Administrator. It usually boils down to these three things: #1) Respect the privacy of others. #2) Think before you type. #3) With great power comes great responsibility. [sudo] password for openfire: Sorry, try again. [sudo] password for openfire: Sorry, try again. [sudo] password for openfire:
最新发布
10-31
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