package cn.com.Inf;
import java.util.Iterator;
//interface
/*................Gist
* The underlying implementation of the collection is implemented with an array
* The collection is not limited by the length of the array, and the storage space will be automatically increased when the space is insufficient
* Set collection cannot have duplicate elements
* Set collection is non-linear
* */
public interface SetADT<T> {
public void add(T element);//Add element
public void addAll(SetADT<T> set);//Add elements from another set to your own set
public T remove(T element);//Remove element
public T removeRandom();//Remove randomly
public boolean contains(T target);//Determine whether there are duplicate elements
public boolean equals(SetADT<T> set);//Determine whether the elements in the two sets are equal
public boolean isEmpty();//Determine whether there is an element in the collection
public SetADT<T> union(SetADT<T> set);//Merge the two sets together
public int size();//The size of the collection
public Iterator<T> iterator();//Iterators need to traverse the collection
public String toString();//Turn the elements in the collection into strings for display
}
package cn.com.MyArrayList;
import java.util.EmptyStackException;
import java.util.Iterator;
import java.util.NoSuchElementException;
import java.util.Random;
import cn.com.Inf.SetADT;
public class MyArrayList<T> implements SetADT<T>{
private T[] content;//Define the array
private int count;//Define an index, equivalent to C, C++ pointer.
private int initCapacity = 100;//Array initialization length 100
Random r= new Random();//Random function, which needs to be used in the random deletion method
public MyArrayList(){
count = 0;
content = (T[])(new Object[initCapacity]);//Initialize an array of 100
}
@Override
public void add(T element) {
// TODO Auto-generated method stub
if(!contains(element)){ //Determine whether there are duplicates////* (required)
if(this.size() == content.length){
expandContent();//The array space is insufficient to call the function to expand the space
}
content[count] = element;
count++;//Add to the array
}
}
private void expandContent() {
// TODO Auto-generated method stub
// increase the array space
T[] target = (T[])(new Object[content.length*2]);
for(int i = 0 ; i < content.length ; i++){
target[i] = content[i];
}
target = content;
}
@Override
public T remove(T element) {
// TODO Auto-generated method stub
boolean bool = false;
int search = -1;
if(isEmpty()){
throw new EmptyStackException();//Determine whether the array is empty
}
for(int i = 0 ; i < content.length; i++){
if(content[i].equals(element)){
search = i;
break;
}
}
if(search == -1){
throw new NoSuchElementException();
}
//Replace the last element with the element currently to be deleted, and delete the last element by count--
T result = content[search];
content[search] = content[count-1];
content[count-1] = null;
count--;
return result;
}
@Override
public T removeRandom() {
// TODO Auto-generated method stub
if(isEmpty()){
throw new EmptyStackException();
}
//Randomly delete elemnt with subscript 0-count-1
int choice = r.nextInt(count);
T result = content[choice];
content[choice] = content[count-1];
content[count-1] = null;
count--;
return result;
}
public boolean contains(T target) {
// TODO Auto-generated method stub
// loop through the array
boolean bool =false;
for(int i = 0; i < count; i++){
if(content[i].equals(target)){
bool = true;
}
}
return bool;
}
@Override
public boolean isEmpty() {
// TODO Auto-generated method stub
return(count==0);
}
@Override
public int size() {
// TODO Auto-generated method stub
return count;
}
@Override
public Iterator<T> iterator() {
// TODO Auto-generated method stub
// instantiate
return new ArrayIterator<T>(content,count);
}
@Override
public boolean equals(SetADT<T> set) {
// TODO Auto-generated method stub
boolean result = false;
//define two sets
MyArrayList<T> temp1 = new MyArrayList<T>();
MyArrayList<T> temp2 = new MyArrayList<T>();
//Check if the set lengths are equal
T obj;
if(this.size() == set.size()){
temp1.addAll(this);
temp2.addAll(set);
Iterator<T> scan = set.iterator();
while(scan.hasNext()){
obj = scan.next();
if(temp1.contains(obj)){
temp1.remove(obj);
temp2.remove(obj);
}
}
// delete one by one
result = ((temp1.isEmpty())&&(temp1.isEmpty()));
}
return result;
}
@Override
public SetADT<T> union(SetADT<T> set) {
// TODO Auto-generated method stub
// merge the two sets
MyArrayList<T> both = new MyArrayList<T>();
for(int i = 0 ; i < count ; i++){
both.add(content[i]);
}
Iterator<T> scan = set.iterator();
while(scan.hasNext()){
both.add(scan.next());
}
return both;
}
public void addAll(SetADT<T> set) {
// TODO Auto-generated method stub
// Traverse one by one and add to the collection
Iterator<T> i = set.iterator();
while(i.hasNext()){
add(i.next());
}
}
public String toString(){
// convert element to string
String result = "";
for(int i = 0 ; i < count; i++){
result = result + content[i].toString()+ "\n";
}
return result;
};
}
package cn.com.MyArrayList;
import java.nio.channels.UnsupportedAddressTypeException;
import java.util.Iterator;
import java.util.NoSuchElementException;
public class ArrayIterator<T> implements Iterator<T> {
private T[] item;
private int count;
private int current;
public ArrayIterator(T[] collection,int size){
//initialize an array
this.item = collection;
this.count = size;
current = 0;
}
@Override
public boolean hasNext() {
// TODO Auto-generated method stub
// Determine if there is a next
return (current < count);
}
@Override
public T next() {
// TODO Auto-generated method stub
T result = null;
if(hasNext()){
result = item[current];
current++;
}else{
throw new NoSuchElementException();
}
return result;
}
@Override
public void remove() {
// TODO Auto-generated method stub
throw new UnsupportedOperationException();
}
}