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    • com.scudata.util.MinHeap Maven / Gradle / Ivy

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    SPL(Structured Process Language) A programming language specially for structured data computing.

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    package com.scudata.util;

import java.util.Comparator;

import com.scudata.dm.comparator.BaseComparator;

/**
 * ????ȡ??С??n??ֵ?Ķ?
 * @author WangXiaoJun
 *
 */
public class MinHeap {
	// ?????(?Ѷ?Ԫ?????)??????Ԫ?ؽ???ʱ?ȸ??Ѷ????бȽϣ?????ȶѶ???????
	private Object []heap; // ???ڱ?????????????ڵ??ֵ??????0??λ?ÿ???
	private int maxSize; // ??ౣ????ֵ??????
	private int currentSize; // ??ǰ???е?ֵ??????
	private Comparator comparator; // ֵ?Ƚ???

	/**
	 * ????ȡmaxSize????Сֵ?Ķ?
	 * @param maxSize ????
	 */
	public MinHeap(int maxSize) {
		this(maxSize, new BaseComparator());
	}
	
	/**
	 * ????ȡmaxSize????Сֵ?Ķ?
	 * @param maxSize ????
	 * @param comparator ?Ƚ???
	 */
	public MinHeap(int maxSize, Comparator comparator) {
		this.heap = new Object[maxSize + 1];
		this.maxSize = maxSize;
		this.currentSize = 0;
		this.comparator = comparator;
	}

	/**
	 * ???ص?ǰ??ֵ????
	 * @return ????
	 */
	public int size() {
		return currentSize;
	}

	/**
	 * ??????ֵ
	 * @param o ֵ
	 * @return true????ǰֵ??ʱ????С??maxSize??ֵ??Χ?ڣ?false????ǰֵ̫?󱻶???
	 */
	public boolean insert(Object o) {
		Object []heap = this.heap;
		if (currentSize == maxSize) {
			if (comparator.compare(o, heap[1]) >= 0) {
				return false;
			} else {
				deleteRoot();
				return insert(o);
			}
		} else {
			int i = ++currentSize;
			while (i != 1 && comparator.compare(o, heap[i/2]) > 0) {
				heap[i] = heap[i/2]; // ??Ԫ??????
				i /= 2;              // ???򸸽ڵ?
			}

			heap[i] = o;
			return true;
		}
	}
	
	/**
	 * ????һ???ѵ????ݼӵ???ǰ??
	 * @param other
	 */
	public void insertAll(MinHeap other) {
		Object []heap = other.heap;
		for (int i = 1, currentSize = this.currentSize; i <= currentSize; ++i) {
			insert(heap[i]);
		}
	}

	/**
	 * ɾ?????ڵ?
	 */
	private void deleteRoot() {
		// ?????һ??Ԫ?ط??ڶѶ???Ȼ???Զ????µ???
		Object []heap = this.heap;
		int currentSize = this.currentSize;
		Object o = heap[currentSize];

		int i = 1;
		int c = 2; // ?ӽڵ?
		while(c < currentSize) {
			// ?ҳ??ϴ???ӽڵ?
			int rc = c + 1;  // ???ӽڵ?
			if (rc < currentSize && comparator.compare(heap[rc], heap[c]) > 0) {
				c = rc;
			}

			if (comparator.compare(o, heap[c]) < 0) {
				heap[i] = heap[c];
				i = c;
				c *= 2;
			} else {
				break;
			}
		}

		heap[i] = o;
		heap[currentSize] = null;
		this.currentSize--;
	}

	/**
	 * ????????Ԫ??
	 * @return Ԫ??????
	 */
	public Object[] toArray() {
		Object []objs = new Object[currentSize];
		System.arraycopy(heap, 1, objs, 0, currentSize);
		//Arrays.sort(objs);
		return objs;
	}
	
	/**
	 * ȡ?Ѷ?Ԫ??
	 * @return
	 */
	public Object getTop() {
		return heap[1];
	}
}
    
    
    
    

    




    
    
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