packageDate_pacage;public class Array{//叫它静态数组//private int[] data;
privateE[] data;private intsize;//构造函数
public Array(intcapacity) {
data= (E[])newObject[capacity];
size= 0;
}//无参数的构造函数，默认数组的容量为10
publicArray() {this(10);
}public intgetSize() {returnsize;
}public booleanisEmpty() {return size == 0;
}public intgetCapacity() {returndata.length;
}//O(1)
public voidaddLast(E e) {
add(size, e);
}//O(n)
public voidaddFirst(E e) {
add(0, e);
}//O(n/2) = O(n)
public void add(intindex, E e) {if(size>=data.length)
resize(2 *data.length);if(index<0 || index>size)throw new IllegalArgumentException("Add failed.index is error.");for(int i=size-1;i>=index;i--) {
data[i+1] =data[i];
}
data[index]=e;
size++;
}
@OverridepublicString toString() {
StringBuilder res= newStringBuilder();
res.append(String.format("Array: size = %d, capacity = %d\n", size, data.length));
res.append("[");for(int i = 0 ; i
res.append(data[i]);if(i != size - 1)
res.append(", ");
}
res.append("]");returnres.toString();
}public E get(intindex) {if(index < 0 || index >=size)throw new IllegalArgumentException("Get failed. Index is illegal");returndata[index];
}publicE getFirst() {return get(size - 1);
}publicE getLast() {return get(0);
}void set(intindex, E e) {if(index < 0 || index >=size)throw new IllegalArgumentException("Get failed. Index is illegal");
data[index]=e;
}public booleancontains(E e) {for(int i = 0; i < size; i++) {if(data[i].equals(e))return true;
}return false;
}public intfind(E e) {for(int i = 0; i < size; i++) {if(data[i].equals(e))returni;
}return -1;
}public E remove(intindex) {if(index < 0 || index >=size)throw new IllegalArgumentException("Get failed. Index is illegal");
E res=data[index];for(int i = index; i
data[i]= data[i+1];
}
size--;//释放空间，也可以不写//loitering objects != memory leak
data[size] = null;if(size == data.length / 4 && data.length / 2 != 0)
resize(data.length/ 2);returnres;
}publicE removeFirst() {return remove(0);
}publicE removeLast() {return remove(size-1);
}//只删除了一个e，并不能保证删除了全部e
public voidremoveElement(E e) {int index =find(e);if(index != -1)
remove(index);
}private void resize(intnewCapacity) {
E[] newData= (E[]) newObject[newCapacity];for(int i=0; i < size; i++) {
newData[i]=data[i];
}
data=newData;
}
}