LeetCode Online Judge 题目C# 练习 - 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.

 

 1         public static int LengthofLastWord(string s)
 2         {
 3             int ret = 0;
 4             int temp = 0;
 5             int index = 0;
 6             while (index < s.Length)
 7             {
 8                 if (s[index] == ' ')
 9                 {
10                     ret = temp == 0 ? ret : temp;
11                     temp = 0;
12                 }
13                 else
14                     temp++;
15                 index++;
16             }
17 
18             ret = temp == 0 ? ret : temp;
19 
20             return ret;
21         }

代码分析：

　　从前往后。

 1         public static int LengthofLastWordOpt(string s)
 2         {
 3             int ret = 0;
 4             int temp = 0;
 5             int index = s.Length - 1;
 6             while (index >= 0)
 7             {
 8                 if (s[index] == ' ')
 9                 {
10                     ret = temp == 0 ? ret : temp;
11                     temp = 0;
12 
13                     if (ret > 0)
14                         return ret;
15                 }
16                 else
17                     temp++;
18                 index--;
19             }
20 
21             ret = temp == 0 ? ret : temp;
22 
23             return ret;
24         }

代码分析：

　　从后往前，计算到最后一个立即返回， 不知道为什么，在LeetCode上test，好像这个performance还差一点。

posted @ 2012-09-19 05:42  ETCOW  阅读(262)  评论(0)  编辑  收藏  举报