[leedcode 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

.

public class Solution {
public int lengthOfLastWord(String s) {
int res=0;
int flag=0;
//解题思路：flag代表后面是否出现过非空格的字符，当flag=1代表后面出现非空格，并且该字符为空格时，遍历结束

/* for(int i=s.length()-1;i>=0;i--){
if(s.charAt(i)!=' '){
res++;
flag=1;
}else if(flag==1&&s.charAt(i)==' ')
break;
}
return res;*/
//////////////第二种方式，先排除最后一位是空格的情况，本题题意“a ”应该返回1
int i=s.length()-1;
while(i>=0){
if(s.charAt(i)!=' ')
break;
i--;

}
for(;i>=0;i--){
if(s.charAt(i)==' ')
return res;
else if(s.charAt(i)!=' '){
res++;
}
}
return res;
}
}