hw3/task3/MyArrayList.java - master - alim4ik-had/SberJavaCourseBeginner

hw3/task3/MyArrayList.java
94 строки2 KB
alimo
оптимизация списка (task3)
26 апр 2025, 12:37
26 апр 2025, 12:379df9ea8
package hw3.task3;

import java.util.Arrays;
import java.util.Iterator;
import java.util.stream.Collectors;
import java.util.stream.IntStream;

public class MyArrayList<T> implements Iterable<T>{
    private int size;
    private T[] data;

    @SuppressWarnings("unchecked")
    public MyArrayList(){
        this.size = 0;
        this.data = (T[]) new Object[10];
    }
    @SuppressWarnings("unchecked")
    public MyArrayList(int size){
        this.size = size;
        this.data = (T[]) new Object[size];
    }

    public MyArrayList(T[] srcData){
        this.size = srcData.length;
        this.data = srcData;
    }

    public int size(){
        return size;
    }

    public T get(int index){
        return data[index];
    }

    public int getIndex(T element){
        return IntStream.range(0, size)
                .filter(i -> data[i].equals(element))
                .findFirst()
                .orElse(-1);
    }

    public int add(T element){
        if(size == data.length){
            ensureSize();
        }
        data[size++] = element;
        return size-1;
    }

    public boolean contains(T element){
        return Arrays.stream(data).anyMatch(x -> x.equals(element));
    }

    public boolean remove(T element){
        int elementIndex = getIndex(element);
        if(elementIndex == -1) return false;

        System.arraycopy(data, elementIndex+1, data, elementIndex, size - elementIndex - 1);
        size--;
        return true;
    }

    public boolean removeByIndex(int index){
        if(index < 0 || index >= size) return false;
        System.arraycopy(data, index+1, data, index, size - index - 1);
        size--;
        return true;
    }

    @Override
    public Iterator<T> iterator(){
        return new MyIterator<T>(size, data);
    }

    @Override
    public String toString() {
        StringBuilder output = new StringBuilder("[");
        for (int i = 0; i < size; i++){
            output.append(data[i]);
            if(i < size -1)
                output.append(", ");
        }
        output.append("]");
        return output.toString();
    }
    private void ensureSize(){
        int newSize = data.length * 2;
        T[] newData = (T[])new Object[newSize];
        System.arraycopy(data, 0, newData, 0, size);
        data = newData;
    }

}