LeetCode | 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.

简单题。注意某些特殊情况，比如”a “这样的，要过滤掉尾部的空格。

class Solution {
public:
int lengthOfLastWord(string s) {
int len = s.length();
int back = len-1;       //过滤尾部空格
while(s[back] == ' ')
back--;

if(back < 0)
return 0;

for(int i=back;i>=0;i--)
{
if(s[i] == ' ')
return back-i;
}
//没有遇到空格
return back+1;
}
};