shz.core.stack.a.LArrayStack Maven / Gradle / Ivy
package shz.core.stack.a;
import java.util.Arrays;
/**
* 元素类型为E基于动态数组的栈
*
* 24+[8+E(类型字节)]*n(n为元素个数)=es
*
* B=48+8*n+(E*n+对齐填充)
*/
@SuppressWarnings("unchecked")
public class LArrayStack extends ArrayStack {
protected E[] es;
protected LArrayStack(int capacity) {
super(capacity);
es = (E[]) new Object[capacity];
}
public static LArrayStack of(int capacity) {
return new LArrayStack<>(capacity);
}
public static LArrayStack of() {
return of(DEFAULT_CAPACITY);
}
@Override
protected final E get(int i) {
return es[i];
}
@Override
protected final void resize(int capacity) {
this.capacity = capacity;
es = Arrays.copyOf(es, capacity);
}
@Override
protected final void setNull(int i) {
es[i] = null;
}
public final void push(E e) {
beforePush();
es[size++] = e;
}
public final E pop() {
E e = es[--size];
afterPop();
return e;
}
public final E peek() {
return es[size - 1];
}
public final void reverse() {
if (size == 0) return;
//栈底移至栈顶
bottomToTop();
E top = es[size - 1];
pop();
reverse();
push(top);
}
private void bottomToTop() {
if (size == 0) return;
E top1 = es[size - 1];
pop();
if (size == 0) push(top1);
else {
bottomToTop();
E top2 = es[size - 1];
pop();
//交换栈顶 与 子栈顶
push(top1);
push(top2);
}
}
}