华为的一道上机题，我用java写怎么老是莫名其妙的异常呢？

[fengzhe0411]

问题描述：
在给定字符串中找出单词（ “单词”由大写字母和小写字母字符构成，其他非字母字符视为单词的间隔，如空格、问号、数字等等；另外单个字母不算单词）；找到单词后，按照长度进行降序排序，（排序时如果长度相同，则按出现的顺序进行排列），然后输出到一个新的字符串中；如果某个单词重复出现多次，则只输出一次；如果整个输入的字符串中没有找到单词，请输出空串。输出的单词之间使用一个“空格”隔开，最后一个单词后不加空格。
要求实现函数：

import java.util.Scanner;
import java.util.Set;
import java.util.TreeSet;

public class StringSort {
	public static void main(String[] args) {
		Scanner in = new Scanner(System.in);
		String s = in.next();
		
		int subLength = 0;
		StringBuilder sb = new StringBuilder();
		Set<MyString> strs = new TreeSet<MyString>();
		for(int i=0;i<s.length();i++){
			char c = s.charAt(i);
			if((c<='z'&&c>='a')||(c<='Z'&&c>='A')){
				subLength++;
				sb.append(c);
			}
			else
			{
				if(subLength!=0){
					System.out.println(sb.toString()+" "+subLength);
					strs.add(new MyString(sb.toString(), subLength));
					sb.delete(0,sb.capacity());
					subLength = 0;
				}
			}
		}
		
		if(subLength!=0){
			System.out.println(sb.toString()+" "+subLength);
			strs.add(new MyString(sb.toString(), subLength));
		}
		
		java.util.Iterator<MyString> it = strs.iterator();
		while(it.hasNext()){
			MyString myString = it.next();
			System.out.println(myString.subStr);
		}
	}
}

class MyString implements Comparable<MyString>{
	String subStr;
	int subLength;
	
	public MyString(String subStr, int subLength) {
		this.subStr = subStr;
		this.subLength = subLength;
	}

	@Override
	public int compareTo(MyString o) {
		if(this.subLength>o.subLength)
			return -1;
		else if(this.subLength>o.subLength)
			return 1;
		else
			return 0;
	}

	@Override
	public boolean equals(Object obj) {
		return this.subStr.equals(((MyString)obj).subStr);
	}
	
	
	
}

调试的时候每次运行到遍历treeset的时候就会跳到Thread的异常里面去，实在不解

[fengzhe0411]

问题不在我说的那里 应该出在MyString的compare和equals方法上

[lurengu00]

面试可以用库函数不？
字符串用正则表达式匹配下，得到的串分别塞到自写类MyString里面，MyString实现个Comparable接口覆盖equals全部塞到TreeSet里面打印下，这种允许么？

[xuyajun2013]

package com.xyj.test;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;

public class Test6 {
private static List<String> list = new LinkedList<String>();

public static void main(String[] args) {
BufferedReader reader = null;
try {
reader = new BufferedReader(new InputStreamReader(System.in));
String str = reader.readLine();

List<String> list = getWordList(str);

List<String> reList = sortWordByLength(list);
for(Iterator<String> iter=reList.iterator(); iter.hasNext();) {
System.out.println(iter.next());
}

} catch (IOException e) {
e.printStackTrace();
} finally {
if(reader != null) {
try {
reader.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}

public static List<String> getWordList(String str) {
StringBuilder sb = new StringBuilder();
for(int i=0; i<str.length(); i++) {
char c = str.charAt(i);
if(c<='z'&&c>='a' || c<='Z'&&c>='A') {
sb.append(c);
} else {
if(sb.length()!=0 && !"".equals(sb.toString().trim())) {
list.add(sb.toString());
}

sb = new StringBuilder();
}

if(i == str.length()-1) {
if(sb.capacity() != 0) {
list.add(sb.toString());
}
}
}

return list;
}

public static List<String> sortWordByLength(List<String> list) {
List<String> reList = new ArrayList<String>();

int size = list.size();
int totalSize = size;

while(reList.size() < totalSize) {
int maxLength = 0;
int maxIndex = 0;
for(int i=0; i<size; i++) {
int len = list.get(i).length();
if(len > maxLength) {
maxLength = len;
maxIndex = i;
}
}

reList.add(list.get(maxIndex));
list.remove(maxIndex);
size--;
}

return reList;
}
}

[Sad4This]

我想楼主的compare方法写错了

public int compareTo(MyString o) {
        if(this.subLength>o.subLength)
            return -1;
        else if(this.subLength>o.subLength)  // 这里跟上个if条件一样
            return 1;
        else
            return 0;
    }

应该改为

public int compareTo(MyString o) {
        if(this.subLength>o.subLength)
            return -1;
        else if(this.subLength<o.subLength)
            return 1;
        else
            return 0;
    }

试试

[杀手]

收下。。。。

[杀手]

package huawei.exam;

import java.util.ArrayList;
import java.util.List;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class StringSort {
	private List<String> words = new ArrayList<String>();

	public void getWords(String test_str) {
		Pattern p = Pattern.compile("[a-zA-Z]{2,}+");
		Matcher m = p.matcher(test_str);
		while (m.find()) {
			String tmp_str = m.group();
			if (check(tmp_str))
				words.add(getindex(tmp_str),tmp_str);
		}
	}

	private boolean check(String tmp_str) {
		if (words.contains(tmp_str)) {
			return false;
		} else {
			return true;
		}
	}

	private int getindex(String tmp_str){
		int tmp_length = tmp_str.length();
		int words_length = words.size();
		if(words_length==0){
			return 0;
		}
		else{
			for(int i =0;i<words_length;i++){
				if(tmp_length >= words.get(i).length()){
					continue;
				}else{
					return i;
				}
				
			}
			return words_length;
		}
	}
	
	private String newString() {
		String newString = "";
		
		for(int i =0;i<words.size();i++){
			if(i!= words.size()-1)
				newString += words.get(i)+" ";
			else
				newString += words.get(i);
		}
		
		return newString;
	}

	public static void main(String[] args) {
		StringSort ss = new StringSort();
		ss.getWords("hello12dd21 we / ;dw");
		System.out.println(ss.newString());
	}
}

[loveceltics]

楼主哪个地区的，华为这么早就面试了啊

[ishuiyutian]

static class MyString implements Comparable<MyString>{
		String str;
		public MyString(String str){
			this.str = str;
		}
		
		@Override
		public int compareTo(MyString obj) {
			if(equals(obj)){
				return 0;
			}
			if(str.length() > obj.str.length()){
				return -1;
			}
			else{
				return 1;
			}
		}

		@Override
		public boolean equals(Object obj) {
			if(!(obj instanceof MyString)){
				return false;
			}
			MyString temp = (MyString)obj;
			if(!str.equals(temp.str)){
				return false;
			}
			return true;
		}
		
		
	}