题解 | 字符串最后一个单词的长度

import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        StringBuilder sb = new StringBuilder();
        while (in.hasNextLine()) {
            sb.append(in.nextLine());
        }
	  	// reverse input string, then trim it
        String trim = sb.reverse().toString().trim();
	  	// find first blank char
        int i = trim.indexOf(" ");
	  	// if not find, just one word
        System.out.println(i > 0 ? i : trim.length());
    }
}

直接使用JDK库, 简单搞定