package datastructure.stack;
public class Array {
private E[] data;
private int size;
// æž„é€ å‡½æ•°ï¼Œä¼ å…¥æ•°ç»„çš„å®¹é‡capacityæž„é€ Array
public Array(int capacity){
data = (E[])new Object[capacity];
size = 0;
}
// æ— å‚æ•°çš„æž„é€ å‡½æ•°ï¼Œé»˜è®¤æ•°ç»„çš„å®¹é‡capacity=10
public Array(){
this(10);
}
// 获å–数组的容é‡
public int getCapacity(){
return data.length;
}
// 获å–数组ä¸çš„å…ƒç´ ä¸ªæ•°
public int getSize(){
return size;
}
// 返回数组是å¦ä¸ºç©º
public boolean isEmpty(){
return size == 0;
}
// 在index索引的ä½ç½®æ’å…¥ä¸€ä¸ªæ–°å…ƒç´ e
public void add(int index, E e){
if(index < 0 || index > size)
throw new IllegalArgumentException("Add failed. Require index >= 0 and index <= size.");
if(size == data.length)
resize(2 * data.length);
for(int i = size - 1; i >= index ; i --)
data[i + 1] = data[i];
data[index] = e;
size ++;
}
// å‘æ‰€æœ‰å…ƒç´ åŽæ·»åŠ 一个新元ç´
public void addLast(E e){
add(size, e);
}
// åœ¨æ‰€æœ‰å…ƒç´ å‰æ·»åŠ 一个新元ç´
public void addFirst(E e){
add(0, e);
}
// 获å–index索引ä½ç½®çš„å…ƒç´
public E get(int index){
if(index < 0 || index >= size)
throw new IllegalArgumentException("Get failed. Index is illegal.");
return data[index];
}
public E getLast(){
return get(size - 1);
}
public E getFirst(){
return get(0);
}
// 修改index索引ä½ç½®çš„å…ƒç´ ä¸ºe
public void set(int index, E e){
if(index < 0 || index >= size)
throw new IllegalArgumentException("Set failed. Index is illegal.");
data[index] = e;
}
// 查找数组ä¸æ˜¯å¦æœ‰å…ƒç´ e
public boolean contains(E e){
for(int i = 0 ; i < size ; i ++){
if(data[i].equals(e))
return true;
}
return false;
}
// 查找数组ä¸å…ƒç´ e所在的索引，如果ä¸å˜åœ¨å…ƒç´ e，则返回-1
public int find(E e){
for(int i = 0 ; i < size ; i ++){
if(data[i].equals(e))
return i;
}
return -1;
}
// 从数组ä¸åˆ 除indexä½ç½®çš„å…ƒç´ , è¿”å›žåˆ é™¤çš„å…ƒç´
public E remove(int index){
if(index < 0 || index >= size)
throw new IllegalArgumentException("Remove failed. Index is illegal.");
E ret = data[index];
for(int i = index + 1 ; i < size ; i ++)
data[i - 1] = data[i];
size --;
data[size] = null; // loitering objects != memory leak
if(size == data.length / 4 && data.length / 2 != 0)
resize(data.length / 2);
return ret;
}
// 从数组ä¸åˆ é™¤ç¬¬ä¸€ä¸ªå…ƒç´ , è¿”å›žåˆ é™¤çš„å…ƒç´
public E removeFirst(){
return remove(0);
}
// 从数组ä¸åˆ 除最åŽä¸€ä¸ªå…ƒç´ , è¿”å›žåˆ é™¤çš„å…ƒç´
public E removeLast(){
return remove(size - 1);
}
// 从数组ä¸åˆ é™¤å…ƒç´ e
public void removeElement(E e){
int index = find(e);
if(index != -1)
remove(index);
}
@Override
public String toString(){
StringBuilder res = new StringBuilder();
res.append(String.format("Array: size = %d , capacity = %d\n", size, data.length));
res.append('[');
for(int i = 0 ; i < size ; i ++){
res.append(data[i]);
if(i != size - 1)
res.append(", ");
}
res.append(']');
return res.toString();
}
// 将数组空间的容é‡å˜æˆnewCapacity大å°
private void resize(int newCapacity){
E[] newData = (E[])new Object[newCapacity];
for(int i = 0 ; i < size ; i ++)
newData[i] = data[i];
data = newData;
}
}