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MyArrayList.java
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MyArrayList.java
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import java.util.Arrays;
public class MyArrayList<E> {
private static final int DEFAULT_CAPACITY = 10;
private Object[] elements;
private int size;
public MyArrayList() {
this(DEFAULT_CAPACITY);
}
public MyArrayList(int initialCapacity) {
this.elements = new Object[initialCapacity];
this.size = 0;
}
public int size() {
return size;
}
public void add(E element) {
ensureCapacity(size + 1);
elements[size++] = element;
}
@SuppressWarnings("unchecked")
public E get(int index) {
checkForOutOfBounds(index);
return (E) elements[index];
}
public void set(int index, E element) {
checkForOutOfBounds(index);
elements[index] = element;
}
public boolean remove(int index) {
checkForOutOfBounds(index);
int numToMove = size - (index + 1);
if (numToMove > 0) {
System.arraycopy(elements, index + 1, elements, index, numToMove);
}
elements[--size] = null;
return true;
}
private void ensureCapacity(int minCapacity) {
if (minCapacity > elements.length) {
int newCapacity = elements.length + (elements.length >> 1); // adding 50% capacity
elements = Arrays.copyOf(elements, newCapacity);
}
}
private void checkForOutOfBounds(int index) {
if (index < 0 || index >= size) {
throw new IndexOutOfBoundsException("Index: " + index + ", Size: " + size);
}
}
public String toString() {
if (size == 0)
return "[ ]";
StringBuilder sb = new StringBuilder();
sb.append("[ ");
for (int i = 0; i < size - 1; i++) {
sb.append(elements[i]).append(", ");
}
sb.append(elements[size - 1]).append(" ]");
return sb.toString();
}
}