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translation: Add Python and Java code for EN version (#1345)
* Add the intial translation of code of all the languages * test * revert * Remove * Add Python and Java code for EN version
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/**
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* File: my_heap.java
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* Created Time: 2023-01-07
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* Author: krahets (krahets@163.com)
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*/
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package chapter_heap;
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import utils.*;
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import java.util.*;
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/* Max-heap */
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class MaxHeap {
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// Use list instead of array to avoid the need for resizing
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private List<Integer> maxHeap;
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/* Constructor, build heap based on input list */
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public MaxHeap(List<Integer> nums) {
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// Add all list elements into the heap
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maxHeap = new ArrayList<>(nums);
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// Heapify all nodes except leaves
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for (int i = parent(size() - 1); i >= 0; i--) {
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siftDown(i);
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}
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}
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/* Get index of left child node */
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private int left(int i) {
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return 2 * i + 1;
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}
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/* Get index of right child node */
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private int right(int i) {
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return 2 * i + 2;
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}
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/* Get index of parent node */
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private int parent(int i) {
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return (i - 1) / 2; // Integer division down
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}
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/* Swap elements */
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private void swap(int i, int j) {
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int tmp = maxHeap.get(i);
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maxHeap.set(i, maxHeap.get(j));
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maxHeap.set(j, tmp);
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}
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/* Get heap size */
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public int size() {
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return maxHeap.size();
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}
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/* Determine if heap is empty */
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public boolean isEmpty() {
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return size() == 0;
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}
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/* Access heap top element */
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public int peek() {
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return maxHeap.get(0);
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}
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/* Push the element into heap */
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public void push(int val) {
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// Add node
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maxHeap.add(val);
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// Heapify from bottom to top
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siftUp(size() - 1);
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}
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/* Start heapifying node i, from bottom to top */
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private void siftUp(int i) {
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while (true) {
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// Get parent node of node i
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int p = parent(i);
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// When "crossing the root node" or "node does not need repair", end heapification
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if (p < 0 || maxHeap.get(i) <= maxHeap.get(p))
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break;
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// Swap two nodes
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swap(i, p);
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// Loop upwards heapification
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i = p;
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}
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}
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/* Element exits heap */
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public int pop() {
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// Empty handling
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if (isEmpty())
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throw new IndexOutOfBoundsException();
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// Swap the root node with the rightmost leaf node (swap the first element with the last element)
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swap(0, size() - 1);
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// Remove node
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int val = maxHeap.remove(size() - 1);
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// Heapify from top to bottom
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siftDown(0);
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// Return heap top element
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return val;
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}
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/* Start heapifying node i, from top to bottom */
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private void siftDown(int i) {
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while (true) {
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// Determine the largest node among i, l, r, noted as ma
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int l = left(i), r = right(i), ma = i;
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if (l < size() && maxHeap.get(l) > maxHeap.get(ma))
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ma = l;
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if (r < size() && maxHeap.get(r) > maxHeap.get(ma))
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ma = r;
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// If node i is the largest or indices l, r are out of bounds, no further heapification needed, break
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if (ma == i)
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break;
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// Swap two nodes
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swap(i, ma);
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// Loop downwards heapification
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i = ma;
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}
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}
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/* Print heap (binary tree) */
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public void print() {
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Queue<Integer> queue = new PriorityQueue<>((a, b) -> { return b - a; });
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queue.addAll(maxHeap);
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PrintUtil.printHeap(queue);
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}
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}
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public class my_heap {
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public static void main(String[] args) {
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/* Initialize max-heap */
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MaxHeap maxHeap = new MaxHeap(Arrays.asList(9, 8, 6, 6, 7, 5, 2, 1, 4, 3, 6, 2));
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System.out.println("\nEnter list and build heap");
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maxHeap.print();
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/* Access heap top element */
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int peek = maxHeap.peek();
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System.out.format("\nTop element of the heap is %d\n", peek);
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/* Push the element into heap */
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int val = 7;
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maxHeap.push(val);
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System.out.format("\nAfter element %d is added to the heap\n", val);
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maxHeap.print();
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/* Pop the element at the heap top */
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peek = maxHeap.pop();
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System.out.format("\nAfter the top element %d is removed from the heap\n", peek);
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maxHeap.print();
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/* Get heap size */
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int size = maxHeap.size();
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System.out.format("\nNumber of elements in the heap is %d\n", size);
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/* Determine if heap is empty */
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boolean isEmpty = maxHeap.isEmpty();
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System.out.format("\nIs the heap empty %b\n", isEmpty);
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}
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}
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