Length of Last Word

一、题目

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.

给定一个字符串, 包含大小写字母、空格' ',请返回其最后一个单词的长度。

如果不存在最后一个单词,请返回 0

二、解题思路

关键点在于确定最后一个字符串之前的空格,此外还需要考虑末尾空格这一特殊情况。从最后往前扫描。

三、解题代码

public class Solution {
    public int lengthOfLastWord(String s) {
        if (s == null || s.isEmpty()) return 0;

        int len = 0;
        for (int i = s.length() - 1; i >= 0; i--) {
            if (s.charAt(i) == ' ') {
                if (len > 0) return len;
            } else {
                len++;
            }
        }

        return len;
    }
}