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;
// }
}