Share the printing code of the binary heap in Java, and share the java binary

Share the printing code of the binary heap in Java, and share the java binary

A binary heap is a special heap. A binary heap is a completely binary tree (Binary Tree) or an almost completely binary tree (Binary Tree ). There are two types of binary heap: Maximum heap and minimum heap. Max heap: the key value of the parent node is always greater than or equal to the key value of any subnode; min heap: the key value of the parent node is always less than or equal to the key value of any subnode.

Print binary heap: using hierarchical relationships

I sorted the heap first, and then executed the print heap method in sort.printAsTree()

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, number set heap 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 array the cursor mark of an element * @ param B data array * @ Return indicates the maximum value of an element. */private int max (int a, int B) {if (data [a]. compareTo (data [B]) <0) {// If data [B] Big return B; // return B} else {// If data [a] Big return; // return a}/*** @ param a data array. The cursor mark of an element * @ param B data array * @ param c data array * @ return indicates the maximum value of an element. */private int max (int, int B, int c) {int biggest = max (a, B); biggest = max (biggest, c); return biggest;} publ Ic void shiftDown (int father) {while (true) {int lchild = father * 2; int rchild = father * 2 + 1; int newFather = father; // It doesn't matter if the value is assigned here. if you change the return value to break, you must assign the value if (lchild> size) {// if there is no left or right child return ;} else if (rchild> size) {// if there is no right child newFather = max (father, lchild);} else {// if there is left or right child newFather = max (father, lchild, rchild);} if (newFather = father) {// if the original parent node is the maximum of the three nodes, you do not need to refresh the heap return;} el Se {// if the parent node is not the largest, swap the big child up and continue the heap adjustment until swap (newFather, father) is satisfied; father = newFather; // continue shiftDown (newFather ). If newFather is a left child of father, it is equivalent to shiftDown (2 * father) }}public static <T extends Comparable <? Super T> void sort (T [] arr) {int len = arr. length; MaxHeap <T> maxHeap = new MaxHeap <> (arr); maxHeap. printAsTree (); 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 void printSpace (int n) {// print n spaces (replace '\ t' here) for (int I = 0; I <n; I ++) {System. out. printf ("% 3 s", "") ;}} public void printAsTree () {int lineNum = 1; // first traverse the first line of int lines = (int) (Math. log (size)/Math. log (2) + 1; // lines is the number of heap layers int spaceNum = (int) (Math. pow (2, lines)-1); for (int I = 1; I <= size;) {// because in [1... size] data is stored in the left closed right closed interval, and data [0] does not store data // This interval is printed on each layer [2 ^ (layers-1 )... (2 ^ layers)-1]. If the number in the heap is not enough (2 ^ layers)-1, print it to the size. Therefore, min (2 ^ layers)-1, size) is used ). for (int j = (int) Math. pow (2, lineNum-1); j <= Math. min (size, (int) Math. pow (2, lineNum)-1); j ++) {printSpace (spaceNum); // print spaceNum space System. out. printf ("% 3 s", data [j]); // print the data System. out. printf ("% 3 s", ""); // The Green Box printSpace (spaceNum) in the image; // print spaceNum space I ++; // + 1} lineNum ++ for each printed element; spaceNum = spaceNum/2; System. out. println () ;}} public static void main (String args []) {Integer [] arr = {3, 5, 1, 7, 2, 9, 8, 0, 4, 6, 1, 3, 6, 1, 1}; sort (arr );}}

Execution result:

Summary

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