You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
67 lines
2.1 KiB
67 lines
2.1 KiB
/**
|
|
* File: heap.java
|
|
* Created Time: 2023-01-07
|
|
* Author: krahets (krahets@163.com)
|
|
*/
|
|
|
|
package chapter_heap;
|
|
|
|
import utils.*;
|
|
import java.util.*;
|
|
|
|
public class heap {
|
|
public static void testPush(Queue<Integer> heap, int val) {
|
|
heap.offer(val); // Push the element into heap
|
|
System.out.format("\nAfter element %d is added to the heap\n", val);
|
|
PrintUtil.printHeap(heap);
|
|
}
|
|
|
|
public static void testPop(Queue<Integer> heap) {
|
|
int val = heap.poll(); // Pop the element at the heap top
|
|
System.out.format("\nAfter the top element %d is removed from the heap\n", val);
|
|
PrintUtil.printHeap(heap);
|
|
}
|
|
|
|
public static void main(String[] args) {
|
|
/* Initialize the heap */
|
|
// Initialize min-heap
|
|
Queue<Integer> minHeap = new PriorityQueue<>();
|
|
// Initialize the max-heap (using lambda expression to modify Comparator if necessary)
|
|
Queue<Integer> maxHeap = new PriorityQueue<>((a, b) -> b - a);
|
|
|
|
System.out.println("\nThe following test case is for max-heap");
|
|
|
|
/* Push the element into heap */
|
|
testPush(maxHeap, 1);
|
|
testPush(maxHeap, 3);
|
|
testPush(maxHeap, 2);
|
|
testPush(maxHeap, 5);
|
|
testPush(maxHeap, 4);
|
|
|
|
/* Access heap top element */
|
|
int peek = maxHeap.peek();
|
|
System.out.format("\nTop element of the heap is %d\n", peek);
|
|
|
|
/* Pop the element at the heap top */
|
|
testPop(maxHeap);
|
|
testPop(maxHeap);
|
|
testPop(maxHeap);
|
|
testPop(maxHeap);
|
|
testPop(maxHeap);
|
|
|
|
/* Get heap size */
|
|
int size = maxHeap.size();
|
|
System.out.format("\nNumber of elements in the heap is %d\n", size);
|
|
|
|
/* Determine if heap is empty */
|
|
boolean isEmpty = maxHeap.isEmpty();
|
|
System.out.format("\nIs the heap empty %b\n", isEmpty);
|
|
|
|
/* Enter list and build heap */
|
|
// Time complexity is O(n), not O(nlogn)
|
|
minHeap = new PriorityQueue<>(Arrays.asList(1, 3, 2, 5, 4));
|
|
System.out.println("\nEnter list and build min-heap");
|
|
PrintUtil.printHeap(minHeap);
|
|
}
|
|
}
|