一个关于字串的排序算法~~

有如下一些数据：
1-2-3-4-5
2-3-2
2-4-4-2
1-6
保存在一个文本文档中（ANSI编码格式）。要求排序成如下结果：

1-6
1-2-3-4-5
2-4-4-2
2-3-2

即以每一行的最后一个元素进行排序，如果相同再以之前一个排序。都是降序。。

有兴趣的可以试试。

package com.watersoft.file;

import java.io.BufferedReader;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;

public class Sort {
	private int lineCount;
	private int numberCount;
	private String path;
	private int[][] matrix;

	/**
	 * *
	 * 
	 * @param args
	 *            contains the path of a text file which include the data being
	 *            sorted
	 */
	public static void main(String[] args) {
		if (args.length < 1) {
			System.err.println("Specific a file please!");
			return;
		}
		System.out.println(">>> Information: sort start ..\n");
		Sort s = new Sort();
		s.setPath(args[0]);
		s.doSort();
		s.display();
		System.out.println("\n>>> Information: sort end ..");
	}

	/** * do sort: initialize, parse, then sort. */
	public void doSort() {
		init();
		parse();
		for (int index = 0; index < this.lineCount - 1; index++)
			for (int innerIndex = 0; innerIndex < this.lineCount - 1; innerIndex++)
				sort(innerIndex, this.numberCount - 1);
	}

	/**
	 * * sort the given data according to the given row index and column index *
	 * 
	 * @param rowIndex
	 *            current row *
	 * @param colIndex
	 *            current column
	 */
	private void sort(int rowIndex, int colIndex) {
		int aInt = this.matrix[rowIndex][colIndex];
		int bInt = this.matrix[rowIndex + 1][colIndex];
		int temp = 0;
		if (aInt < bInt) { /* * swap two rows */
			for (int index = 0; index < this.numberCount; index++) {
				temp = this.matrix[rowIndex][index];
				this.matrix[rowIndex][index] = this.matrix[rowIndex + 1][index];
				this.matrix[rowIndex + 1][index] = temp;
			}
		} else if (aInt == bInt) { /* * compare previous elements of two rows */
			colIndex--;
			sort(rowIndex, colIndex);
		}
	}

	/**
	 * * read file to make sure the dimension of matrix *
	 * 
	 * @return boolean value, true if successfully done, else false
	 */
	private boolean init() {
		try {
			FileReader fr;
			fr = new FileReader(this.path);
			BufferedReader br = new BufferedReader(fr);
			String tempString;
			int lc = 0;
			int nc = 0;
			while ((tempString = br.readLine()) != null) {
				lc++;
				nc = (nc < tempString.split("-").length) ? tempString
						.split("-").length : nc;
			}
			this.lineCount = lc;
			this.numberCount = nc;
		} catch (FileNotFoundException e) {
			System.err.println("Error: cannot find file:[" + this.path + "]");
			return false;
		} catch (IOException e) {
			System.err.println("Error: cannot read file..");
			return false;
		}
		return true;
	}

	private boolean parse() { /* * initialize matrix */
		this.matrix = new int[this.lineCount][this.numberCount];
		for (int index = 0; index < this.lineCount; index++)
			for (int innerIndex = 0; innerIndex < this.numberCount; innerIndex++)
				this.matrix[index][innerIndex] = Integer.MAX_VALUE;
		try {
			FileReader fr;
			fr = new FileReader(this.path);
			BufferedReader br = new BufferedReader(fr);
			String tempString;
			String[] tempArray;
			int lc = 0;
			int baseIndex = 0;
			while ((tempString = br.readLine()) != null) {
				tempArray = tempString.split("-");
				baseIndex = this.numberCount - tempArray.length;
				for (int index = baseIndex; index < this.numberCount; index++)
					this.matrix[lc][index] = Integer.parseInt(tempArray[index
							- baseIndex]);
				lc++;
			}
		} catch (FileNotFoundException e) {
			System.err.println("Error: cannot find file:[" + this.path + "]");
			return false;
		} catch (IOException e) {
			System.err.println("Error: cannot read file..");
			return false;
		}
		return true;
	}

	/** * display sorted result */
	public void display() {
		for (int index = 0; index < this.lineCount; index++) {
			for (int innerIndex = 0; innerIndex < this.numberCount; innerIndex++) {
				if (this.matrix[index][innerIndex] != Integer.MAX_VALUE)
					if (innerIndex + 1 != this.numberCount)
						System.out.print(this.matrix[index][innerIndex] + "-");
					else
						System.out.print(this.matrix[index][innerIndex]);
			}
			System.out.println();
		}
	}

	public void setPath(String path) {
		this.path = path;
	}
}

评论

3 楼 jossion12 2009-12-15  

我想到一个方法不知道可以不？
把数字补齐，然后反方向变成long，比较大小，按照比较后的顺序把原文排序。
说明：
1-2-3-4-5
2-3-2
2-4-4-2
1-6
补齐：
1-2-3-4-5①
0-0-2-3-2②
0-2-4-4-2③
0-0-0-1-6④
反向变成long：
54321
23200
24420
61000
排序：
61000④
54321①
24420③
23200②

2 楼 raomengwen 2009-09-04  

我觉得有一个最好的办法：
思路：1.先将每个字符串赋值给一个String；
、     2.讲String集体给byte[]
      4.根据byte的最后一个字符的值来比较；这样很方便；

1 楼 zhy20045923 2009-08-04  

<pre name="code" class="java">package test;

import java.io.BufferedReader;
import java.io.FileReader;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Iterator;
import java.util.List;

public class StringSort {

public static void main(String[] args){
StringSort ss = new StringSort();
//you'd better judge the null
List&lt;String&gt; number = ss.sortString(ss.readString());
ss.printResult(number);
}


//read string from file
private List&lt;String&gt; readString(){
List&lt;String&gt; initString = new ArrayList&lt;String&gt;();
try {
BufferedReader readFile = new BufferedReader(new FileReader("C://string.txt"));
String tempstring;
while(null != (tempstring = readFile.readLine())){
initString.add(ConvertString(tempstring));
}
return initString;
}catch (Exception e) {
e.printStackTrace();
return null;
}
}

// reverse and delete '-' from string 
private String ConvertString(String number){
String[] tempSting = number.split("-");
List&lt;String&gt; tempList = new ArrayList&lt;String&gt;();
for(int i=tempSting.length-1;i&gt;=0;i--){
tempList.add(tempSting[i]);
}
return tempList.toString();
}

// sort the List
private List&lt;String&gt; sortString(List&lt;String&gt; list){
List&lt;String&gt; result = new ArrayList&lt;String&gt;();
//sort
Collections.sort(list);
//reverse
Collections.reverse(list);
// result collection
for(int i=0;i&lt;list.size();i++){
String temp = list.get(i).replaceAll("\\D", "");
StringBuffer sb= new StringBuffer();
for(int index = temp.length()-1; index&gt;=0;index--){
sb.append(temp.charAt(index));
sb.append(0 == index ?"":"-");
}
result.add(sb.toString());
}
return result;
}

//print the result
private void printResult(List&lt;String&gt; number){
Iterator i = number.iterator();
while(i.hasNext()){
System.out.println(i.next());
}
}
}
</pre>
<p> </p>