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

.

从字符串的末尾往前遍历。

首先跳过空格。

然后对第一个连续非空格字符串中的字符个数计数。

class Solution {
public:
int lengthOfLastWord(string s) {

int i = s.length()-1;
int len = 0;
while(i>=0 && s[i] == ' ')
--i;
while(i>=0 && s[i] != ' ')
{
++len;
--i;
}

return len;

}
};

class Solution {
public:
int lengthOfLastWord(string s) {

int retLen = 0;
for(int i = 0;i< s.length();i++)
{
while(s[i] == ' ')
i++;
int curLen = 0;
while(s[i] != ' ' && s[i] != '\0')
{
curLen++;
i++;
}
if(curLen != 0)
retLen = curLen;
}
return retLen;

}
};