烟台福山建设工程监测网站百度搜索网页版

在网上看到一道网试题，手痒痒实现了一下，呵呵。

使用Java多线程实现下述算法：
   输入：整数组成的m*n的矩阵A。(m=100000, n=10000)
   输出：一个数列B，数列B中的每一项为矩阵A中对应列数字之和。

 

 1 package com.base.multithread;
 2 
 3 import java.io.IOException;
 4 import java.util.ArrayList;
 5 import java.util.List;
 6 import java.util.Scanner;
 7 
 8 public class PrintMatrix {
 9 
10     public static volatile int count = 0;
11 
12     class ComputeRunnable implements Runnable
13     {
14         private int[][] values = null;
15         private int[] results = null;
16         private int colIndex = 0;
17         
18         public void init(int[][] values,int colIndex,int[] results)
19         {
20             this.values = values;
21             this.colIndex = colIndex;
22             this.results = results;
23             
24         }
25 
26         public void run() {
27             int sum = 0;
28             for(int i = 0 ;i < values.length;i++)
29             {
30                 sum = sum + values[i][colIndex];
31             }
32             results[colIndex] = sum;
33             count++;
34         }
35         
36     }
37     /**
38      * @param args
39      * @throws IOException 
40      * @throws InterruptedException 
41      */
42     public static void main(String[] args) throws IOException, InterruptedException {
43         int m = 0;
44         int n = 0;
45         PrintMatrix pm = new PrintMatrix();
46         System.out.print("Print input m(matrix row):");
47         Scanner scanner = new Scanner(System.in);
48         String srow = scanner.nextLine();
49         System.out.print("Print input n(matrix col):");
50         String scol = scanner.nextLine();
51         m = new Integer(srow).intValue();
52         n  = new Integer(scol).intValue();
53         int[][] arrys = new int[m][n];
54         System.out.println("please input " + m +" * " + n +" matrix,each column with space split:");
55         List<String> lines = new ArrayList<String>();
56         int index = 0;
57         while(scanner.hasNextLine())
58         {
59             lines.add(scanner.nextLine());
60             index++;
61             if(index==m)
62                 break;
63         }
64         //未检查输入正确性
65         for( int i = 0 ;i < m;i++)
66         {
67             String line = lines.get(i);
68             String[] lineArray = line.split(" ");
69             for( int j = 0 ;j < n;j++)
70             {
71                 arrys[i][j] = new Integer(lineArray[j]).intValue();
72             }
73         }
74         int[] results = new int[n];
75         for( int i = 0;i < n ;i++)
76         {
77             ComputeRunnable r = pm.new ComputeRunnable();
78             r.init(arrys,i,results);
79             Thread t = new Thread(r);
80             t.start();
81         }
82         while(true)
83         {
84             if(count == n)
85                 break;
86         }
87         for(int i = 0; i < n;i++)
88             System.out.println("|" + results[i] + "|");
89     }
90     
91     
92 }
93