58. Length of Last Word

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

.

又是个很久以前做的了……当时不知道有个函数叫trim()，现在做就用用一下trim函数把开头结尾的空格去了然后lastIndexOf(" ")找最后一个空格再算一下就好……

public class Solution {
<span style="white-space:pre">	</span>public int lengthOfLastWord(String s) {
<span style="white-space:pre">		</span>int len = s.length();
<span style="white-space:pre">		</span>if (len == 0)
<span style="white-space:pre">			</span>return 0;
<span style="white-space:pre">		</span>if (len == 1 && s.charAt(0) == ' ')
<span style="white-space:pre">			</span>return 0;
<span style="white-space:pre">		</span>len--;
<span style="white-space:pre">		</span>while (len >= 0 && s.charAt(len) == ' ') {
<span style="white-space:pre">			</span>len--;
<span style="white-space:pre">		</span>}
<span style="white-space:pre">		</span>if (len == -1)
<span style="white-space:pre">			</span>return 0;
<span style="white-space:pre">		</span>int a = len;
<span style="white-space:pre">		</span>while (len >= 0 && s.charAt(len) != ' ') {
<span style="white-space:pre">			</span>len--;
<span style="white-space:pre">		</span>}
<span style="white-space:pre">		</span>return (a - len);
<span style="white-space:pre">	</span>}
}