Length of Last Word leetocde java

題目：

Given a string s consists of upper/lower-case alphabets and empty space characters ' ', return the length of last word in the string.

If the last word does not exist, return 0.

Note: A word is defined as a character sequence consists of non-space characters only.

For example,
Given s = "Hello World",
return 5.

 

題解：

 這道題主要是考慮一下最后是不是空格，方法是倒着找不是空格的字符並計數，如果遇到空格且計數不是0，說明最后一個單詞已經被計數了，所以可以返回了。

 

代碼如下：

 
           1      
          public  
          int lengthOfLastWord(String s) { 
          
 
           2           
          if (s ==  
          null || s.length() == 0)   
          
 
           3              
          return 0;   
          
 
           4           
          
 
           5          
          int len = s.length();   
          
 
           6          
          int count = 0;   
          
 
           7          
          for ( 
          int i = len - 1; i >= 0; i--) {   
          
 
           8              
          if (s.charAt(i) != ' ') {   
          
 
           9                 count++;   
          
 
          10             }   
          
 
          11              
          if(s.charAt(i)==' '&&count != 0){   
          
 
          12                  
          return count;   
          
 
          13             }   
          
 
          14         }   
          
 
          15          
          return count;   
          
 
          16     } 
         

 當然這道題也能用投機取巧的方法，用split函數把字符串按照空格分隔好，返回最后那個就行。。。

代碼如下：

 
          1      
          public  
          int lengthOfLastWord(String s) { 
          
 
          2         String[] a = s.split(" "); 
          
 
          3          
          if(a ==  
          null || a.length == 0) 
          
 
          4              
          return 0; 
          
 
          5  
          
 
          6          
          return a[a.length-1].length(); 
          
 
          7     }