线性表

线性表是按顺序存储数据时常用的一种数据结构。实现方式有两种：一种是使用数组，另一种是使用链式结构

接口MyList.java

public interface MyList<E>{
    public void add(E e);
    
    public void add(int index, E e);
    
    public void clear();
    
    public boolean contains(E e);
    
    public E get(int index);
    
    public int indexOf(E e);
        
    public int lastIndexOf(E e);
    
    public boolean isEmpty();
    
    public boolean remove(E e);
    
    public E remove(int index);
    
    public Object set(int index, E e);
    
    public int size();
}

实现接口MyList部分方法的抽象类MyAbstractList.java

public abstract class MyAbstractList<E> implements MyList<E> {
    protected int size = 0;
    
    protected MyAbstractList(){
        
    }
    protected MyAbstractList(E[] objects){
        for(int i = 0; i < objects.length; i++){
            add(objects[i]);
        }
    }
    public void add(E e){
        add(size, e);
    }
    public boolean isEmpty(){
        return size == 0;
    }
    public int size(){
        return size;
    }
    public boolean remove(E e){
        if(indexOf(e) >= 0){
            remove(indexOf(e));
            return true;
        }
        else {
            return false;
        }
    }
}

用数组实现线性表MyArrayList.java

public class MyArrayList<E> extends MyAbstractList<E> {
    public static final int INITIAL_CAPACITY = 16;
    private E[] data = (E[])new Object[INITIAL_CAPACITY];
    
    public MyArrayList(){
        
    }
    public MyArrayList(E[] objects){
        for(int i = 1; i < objects.length; i++){
            add(objects[i]);
        }
    } 
    public void add(int index, E e){
        ensureCapacity();
        for(int i = size -1; i >= index; i--){
            data[i+1] = data[i];
        }
        data[index] = e;
        
        size++;
    }
    public void ensureCapacity(){
        if(size >= data.length){
        E[] newData = (E[])(new Object[size * 2 + 1]);
        System.arraycopy(data, 0, newData, 0, size);
        data = newData;
        }
        
    }
    public void clear(){
        data = (E[])new Object[INITIAL_CAPACITY];
        size = 0;
    }
    public boolean contains(E e){
        for(int i = 0; i < size; i++){
            if(e.equals(data[i]))
                return true;
        }
        return false;
    }
    public E get(int index){
        return data[index];
    }
    public int indexOf(E e){
        for(int i = 0; i < size; i++){
            if(e.equals(data[i])) return i;
        }
        return -1;
    }
    public int lastIndexOf(E e){
        for(int i = size - 1; i >= 0; i--)
            if(e.equals(data[i]))
                return i;
        return -1;
            
    }
    public E remove(int index){
        E e = data[index];
        for(int j = index; j < index - 1; j++)
            data[j] = data[j+1];
        data[size-1] = null;
        size--;
        return e;
    }
    public E set(int index, E e){
        E old = data[index];
        data[index] = e;
        return old;
    }
    public String toString(){
        StringBuilder result = new StringBuilder("[");
        
        for(int i = 0; i < size; i++){
            result.append(data[i]);
            if(i < size - 1) result.append(", ");
        }
        
        return result.toString() + "]";
    }
    public void trimToSize(){
        if(size != data.length){
            E[] newData = (E[])(new Object[size]);
            System.arraycopy(data, 0, newData, 0, size);
            data = newData;
        }
    }
}

线性表测试TestList.java

public class TestList {

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        MyList<String> list = new MyArrayList<String>();
        
        list.add("American");
        System.out.println("(1)"+list);
        
        list.add(0, "Canada");
        System.out.println("(2)"+list);
        
        list.add("Russia");
        System.out.println("(3)"+list);
        
        list.add("France");
        System.out.println("(4)"+list);
        
        list.add(2, "Germany");
        System.out.println("(5)"+list);
        
        list.add(5, "Normay");
        System.out.println("(6)"+list);
        
        list.remove("Canada");
        System.out.println("(7)"+list);
        
        list.remove(2);
        System.out.println("(8)"+list);
        
        list.remove(list.size() - 1);
        System.out.println("(9)"+list);
        
        
    }

}