Thread: my assignment..not able to complete it...please help...

Problem statement: Write a program in java, to compute the union of two large sets.(1 million in each set)

Details: Two sets, A and B, will be provided in the form of two text files 'A.txt' and 'B.txt'. Write a program to read these files into memory, and compute their union. The union of these sets should be written to another file, 'union.txt'. It may be noted that the input sets, A and B, are very large sets containing over a million elements each. Enough thought should be put into the choice of data structures for this program, as it will have a bearing on the efficiency of the program. Also, the design of the program should be well thought out--for example, minimizing the number of passes for reading the input, minimizing the number of times a particular value is computed, etc.

Deliverables:
* the code
* total execution time (measured in terms of CPU time, and not wallclock time)
* a short design document explaining: (a) the algorithm, and (b) the main data structures, along with a justification for their choice.

You've posted your assignment but have yet to ask an answerable question. If you have a question that we can answer, please ask it, and please show any code that you've created so far.

import java.util.*;
import java.io.*;
class assignment{
public static void main(String args[])
throws Exception{
FileReader f1 = new FileReader("c://java/2.txt");
Scanner src= new Scanner(f1);
int a[];
a=new int[1000000];
int i,j;
j=0;
while(src.hasNext())
{if(src.hasNextInt()){
i=src.nextInt();
a[j]=i;

j++;
}

}
f1.close();
FileReader f2 = new FileReader("c://java/3.txt");
Scanner src1= new Scanner(f2);
int b[];
b=new int[1000000];
int k,l;
l=0;
while(src1.hasNext())
{if(src1.hasNextInt()){
k=src1.nextInt();
b[l]=k;
l++;
}


}

f2.close();
int n=a.length+b.length;
int c[]=new int[10];
int p=a.length;
for(i=0;i<a.length;i++)
{
c[i]=a[i];
}
for(i=0;i<b.length;i++)
{
for(j=0;j<a.length;j++)
{
if(b[i]!=c[j])
{continue;}
else{if(b[i]==c[j])break;}}
if(j==10)
c[p++]=b[i];
}
for(i=0;i<n;i++)
{System.out.println(c[i]);}}}

import java.util.*;
import java.io.*;
class assignment{
public static void main(String args[]) 
throws Exception{
FileReader f1 = new FileReader("c://java/2.txt"); 
Scanner src= new Scanner(f1); 
int a[];
a=new int[1000000];
int i,j;
j=0;
while(src.hasNext())
{if(src.hasNextInt()){
i=src.nextInt();
a[j]=i;
 
j++;
}
 
} 
f1.close();
FileReader f2 = new FileReader("c://java/3.txt"); 
Scanner src1= new Scanner(f2); 
int b[];
b=new int[1000000];
int k,l;
l=0;
while(src1.hasNext())
{if(src1.hasNextInt()){
k=src1.nextInt();
b[l]=k;	
l++;
}
 
 
}
 
f2.close();
int n=a.length+b.length;
int c[]=new int[10];
int p=a.length;
for(i=0;i<a.length;i++)
{
c[i]=a[i];
}
for(i=0;i<b.length;i++)
{
for(j=0;j<a.length;j++)
{
if(b[i]!=c[j])
{continue;}
else{if(b[i]==c[j])break;}}
if(j==10)
c[p++]=b[i];
}
for(i=0;i<n;i++)
{System.out.println(c[i]);}}}

--- Update ---

the problem is.. its not printing the union of two arrays.. some problem with the union algorithm for two arrays

two files contain million integers.. m not getting the output

m sorry... i started java just 2 days back.. m totally new...
i tried with smaller inouts..but not wrking..i just need a program from union of two arrays...i feel my logic is wrong for the union..

int n=a.length+b.length;
 
int c[]=new int[10];
 
int p=a.length;
 
 for(i=0;i<a.length;i++)
{
 c[i]=a[i];
}
for(i=0;i<b.length;i++)
{
   for(j=0;j<a.length;j++)
{
    if(b[i]!=c[j])
    {continue;}
          else{if(b[i]==c[j])break;}}
     if(j==10)
     c[p++]=b[i];
}
   for(i=0;i<n;i++)
   {System.out.println(c[i]);}}}

--- Update ---

i googled about indenting a program.. i dint know what it was.. i m sorry for that.. m totally new... is my logic right for the union of two arrays a[] and b[]

its just printing 0000000000