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.

Example:

Input: "Hello World"
Output: 5

solution1：

class Solution {
    public int lengthOfLastWord(String s) {
        int res = 0;
        if(s.length()==0||s==null){
            res = 0;
        }
        else{
            int i = s.length()-1;
           while(i>=0&&s.charAt(i)==' ')
               i--;
            while(i>=0&&s.charAt(i)!=' '){
                i--;
                    res++;
            }
        }
        return res;
    }
}

就是先把尾部的空字符去掉，然后从尾部开始计算长度。

solution2：

熟用method，暴力一行解法

public int lengthOfLastWord(String s) {
    return s.trim().length()-s.trim().lastIndexOf(" ")-1;
}