Length of Last Word

Length of Last Word

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Question Solution 

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.

解法：1.注意字符串两端的空格

  2.字符串比较方法为equals(),字符比较为==

  3 可以使用start来标记最后一个空格的下标，或者使用正则表达式

import java.util.regex.*;public class Solution {        public int lengthOfLastWord(String s) {                if(s==null||"".equals(s.trim())) //注意字符串比较的时候，使用equals()        return 0;                 s=s.trim();         char[] c=s.toCharArray();         int start=0;                  int i=0;         for(;i<c.length;i++){                          if(c[i]==' ') start=i;         }                  return start==0?c.length:c.length-start-1;        }    // public int lengthOfLastWord(String s) {            //     if(s==null||s.trim()=="") return 0;    //     s=s.trim();                          //先去除两端的空格    //     Pattern p=Pattern.compile("([a-zA-Z]+$)");    //     Matcher m=p.matcher(s);    //     int len=0;    //     if(m.find()){    //         String s1=m.group(1);    //         len=s1.length();    //     }            //     return len;    // }}