public class MaxHeap<T extends Comparable<? super T>> { private T[] data; private int size; private int capacity;  public MaxHeap(int capacity) {  this.data = (T[]) new Comparable[capacity + 1];  size = 0;  this.capacity = capacity; }  public int size() {  return this.size; }  public boolean isEmpty() {  return size == 0; }  public int getCapacity() {  return this.capacity; }  /**  * @return 查看最大根(只看不刪, 與popMax對比)  */ public T seekMax() {  return data[1]; }  public void swap(int i, int j) {  if (i != j) {   T temp = data[i];   data[i] = data[j];   data[j] = temp;  } }  public void insert(T item) {  size++;  data[size] = item;  shiftUp(size); }  /**  * @return 彈出最大根(彈出意味著刪除, 與seekMax對比)  */ public T popMax() {  swap(1, size--);  shiftDown(1);  return data[size + 1]; }  /**  * @param child 孩子節點下角標是child，父節點下角表是child/2  */ public void shiftUp(int child) {  while (child > 1 && data[child].compareTo(data[child / 2]) > 0) {   swap(child, child / 2);   child = child / 2;  } }  /**  * @param a data數組中某個元素的下角標  * @param b data數組中某個元素的下角標  * @return 哪個元素大就返回哪個的下角標  */ private int max(int a, int b) {  if (data[a].compareTo(data[b]) < 0) {//如果data[b]大   return b;//返回b  } else {//如果data[a]大   return a;//返回a  } }  /**  * @param a data數組中某個元素的下角標  * @param b data數組中某個元素的下角標  * @param c data數組中某個元素的下角標  * @return 哪個元素大就返回哪個的下角標  */ private int max(int a, int b, int c) {  int biggest = max(a, b);  biggest = max(biggest, c);  return biggest; }   /**  * @param father 父節點下角標是father,左右兩個孩子節點的下角表分別是：father*2 和 father*2+1  */ public void shiftDown(int father) {  while (true) {   int lchild = father * 2;//左孩子   int rchild = father * 2 + 1;//右孩子   int newFather = father;//newFather即將更新，父、左、右三個結點誰大，newFather就是誰的下角標    if (lchild > size) {//如果該father結點既沒有左孩子，也沒有右孩子    return;   } else if (rchild > size) {//如果該father結點只有左孩子，沒有右孩子    newFather = max(father, lchild);   } else {//如果該father結點既有左孩子，又有右孩子    newFather = max(father, lchild, rchild);   }    if (newFather == father) {//說明father比兩個子結點都要大，表名已經是大根堆，不用繼續調整了    return;   } else {//否則，還需要繼續調整堆，直到滿足大根堆條件為止    swap(father, newFather);//值進行交換    father = newFather;//更新father的值，相當于繼續調整shiftDown(newFather)   }  } }  public static <T extends Comparable<? super T>> void sort(T[] arr) {  int len = arr.length;  //入堆  MaxHeap<T> maxHeap = new MaxHeap<T>(len);  for (int i = 0; i < len; i++) {   maxHeap.insert(arr[i]);  }  //出堆  for (int i = len - 1; i >= 0; i--) {   arr[i] = maxHeap.popMax();  } }  public static void printArr(Object[] arr) {  for (Object o : arr) {   System.out.print(o);   System.out.print("/t");  }  System.out.println(); }  public static void main(String args[]) {  Integer[] arr = {3, 5, 1, 7, 2, 9, 8, 0, 4, 6};  printArr(arr);//3 5 1 7 2 9 8 0 4 6  sort(arr);  printArr(arr);//0 1 2 3 4 5 6 7 8 9 }}

public class MaxHeap<T extends Comparable<? super T>> { private T[] data; private int size; private int capacity;  public MaxHeap(int capacity) {  this.capacity = capacity;  this.size = 0;  this.data = (T[]) new Comparable[capacity + 1]; }  public MaxHeap(T[] arr) {//heapify,數組建堆  capacity = arr.length;  data = (T[]) new Comparable[capacity + 1];  System.arraycopy(arr, 0, data, 1, arr.length);  size = arr.length;  for (int i = size / 2; i >= 1; i--) {   shiftDown(i);  } }  public int size() {  return this.size; }  public int getCapacity() {  return this.capacity; }  public boolean isEmpty() {  return size == 0; }  public T seekMax() {  return data[1]; }  public void swap(int i, int j) {  if (i != j) {   T temp = data[i];   data[i] = data[j];   data[j] = temp;  } }  public void insert(T item) {  size++;  data[size] = item;  shiftUp(size); }  public T popMax() {  swap(1, size--);  shiftDown(1);  return data[size + 1]; }  public void shiftUp(int child) {  while (child > 1 && data[child].compareTo(data[child / 2]) > 0) {   swap(child, child / 2);   child /= 2;  } }  /**  * @param a data數組中某個元素的下角標  * @param b data數組中某個元素的下角標  * @return 哪個元素大就返回哪個的下角標  */ private int max(int a, int b) {  if (data[a].compareTo(data[b]) < 0) {//如果data[b]大   return b;//返回b  } else {//如果data[a]大   return a;//返回a  } }  /**  * @param a data數組中某個元素的下角標  * @param b data數組中某個元素的下角標  * @param c data數組中某個元素的下角標  * @return 哪個元素大就返回哪個的下角標  */ private int max(int a, int b, int c) {  int biggest = max(a, b);  biggest = max(biggest, c);  return biggest; }  public void shiftDown(int father) {  while (true) {   int lchild = father * 2;   int rchild = father * 2 + 1;   int newFather = father;//這里賦不賦值無所謂，如果把下面這個return改成break,那就必須賦值了    if (lchild > size) {//如果沒有左、右孩子    return;   } else if (rchild > size) {//如果沒有右孩子    newFather = max(father, lchild);   } else {//如果有左、右孩子    newFather = max(father, lchild, rchild);   }    if (newFather == father) {//如果原父結點就是三者最大，則不用繼續整理堆了    return;   } else {//父節點不是最大，則把大的孩子交換上來，然后繼續往下堆調整，直到滿足大根堆為止    swap(newFather, father);    father = newFather;//相當于繼續shiftDown(newFather)。假如newFather原來是father的左孩子，那就相當于shiftDown(2*father)   }  } }  public static <T extends Comparable<? super T>> void sort(T[] arr) {  int len = arr.length;  MaxHeap<T> maxHeap = new MaxHeap<>(arr);  for (int i = len - 1; i >= 0; i--) {   arr[i] = maxHeap.popMax();  } }  public static void printArr(Object[] arr) {  for (Object o : arr) {   System.out.print(o);   System.out.print("/t");  }  System.out.println(); }  public static void main(String args[]) {  Integer[] arr = {3, 5, 1, 7, 2, 9, 8, 0, 4, 6};  printArr(arr);//3 5 1 7 2 9 8 0 4 6  sort(arr);  printArr(arr);//0 1 2 3 4 5 6 7 8 9 }}