So I created a hashtable with hash chaining(but not sure if it's correct ), For each number in numbers.txt(you can create your own text file for testing with numbers) put it into the hashtable. I timed how long this takes (CPU time). Once the table is loaded, I want to determine how many collisions occurred, that is the question.

And then Output the build time and the collision report to a text file.

import java.io.BufferedWriter;

import java.io.File;

import java.io.FileInputStream;

import java.io.FileNotFoundException;

import java.io.FileWriter;

import java.io.IOException;

import java.util.ArrayList;

import java.util.HashMap;

import java.util.List;

import java.util.Map;

import java.util.Scanner;

public class HashCollisionReport {

public static void main(String[] args) throws IOException {

// Create list from input file

BufferedWriter bw = new BufferedWriter(new FileWriter("Random_Inp.txt"));

List intList = new ArrayList<>();

String fileName = "numbers.txt";

int integerContent = 0;

File file = new File(fileName);

try {

Scanner sc = new Scanner(new FileInputStream(file));

while (sc.hasNextLine()){

integerContent = sc.nextInt();

intList.add(integerContent);

}

sc.close();

}catch(FileNotFoundException fnf){

System.out.println("File not found.");

System.exit(0);

}

catch (Exception e) {

System.out.println(" Program terminated Safely...");

}

//Create Map

Map> intMap = new HashMap<>();

long startTime = System.currentTimeMillis();

for(Integer i : intList){

if (!intMap.containsKey(i.hashCode()%intList.size())){

intMap.put(i.hashCode()%intList.size(), new ArrayList<>());

}

intMap.get(i.hashCode()%intList.size()).add(i);

}

long endTime = System.currentTimeMillis();

String totalTime = (endTime-startTime) + " Milliseconds ";

int totalCollision = 0;

bw = new BufferedWriter(new FileWriter("Collision_Report.txt"));

bw.write("Total CPU Time: " + totalTime);

// Get lsit from each bucket and count nuber of list elements the sum - 1 gives collision of each integer

for(Map.Entry> entry : intMap.entrySet()){

List list = entry.getValue();

int collision = 0;

if(list.size() >= 2){

collision+=list.size()-1;

}

String rep = "Value: " + entry.getKey()+"\t" +" Collison: " + collision + " ";

System.out.println("Value: " + entry.getKey()+"\t" +" Collison: " + collision + " ");

bw.write(rep);

totalCollision += collision;

}

bw.write(" Total Collison: " + totalCollision);

bw.flush();

bw.close();

}

}