标签:没有 oid rabl items while tom 2.4.1 show stat
question:
Implement the constructor for MaxPQ taht takes an array of items as argument, using the bottom-up heap construction method described on page 323 in the text.
answer:
//这里说的bottom-up其实指的就是swim(),当然这样构造堆肯定没有用sink()好
import edu.princeton.cs.algs4.*; public class MaxPQ<Key extends Comparable<Key>> { private Key[] pq; private int N = 0; public MaxPQ(int maxN) { pq = (Key[]) new Comparable[maxN + 1]; } public MaxPQ(Key[] a)//就是这里 { pq = (Key[]) new Comparable[a.length + 1]; for(int i = 0; i < a.length; i++) { pq[i+1] = a[i]; swim(i+1); } } public boolean isEmpty() { return N == 0; } public int size() { return N; } public void insert(Key v) { pq[++N] = v; swim(N); } public Key delMax() { Key max = pq[1]; exch(1,N--); pq[N+1] = null; sink(1); return max; } private boolean less(int i, int j) { return pq[i].compareTo(pq[j]) < 0; } private void exch(int i, int j) { Key t = pq[i]; pq[i] = pq[j]; pq[j] = t; } private void swim(int k) { while(k > 1 && less(k/2,k)) { exch(k/2,k); k/=2; } } private void sink(int k) { while(2*k <= N) { int j = 2*k; if(j < N && less(j,j+1)) j++; if(!less(k,j)) break; exch(k,j); k = j; } } private void show() { for(int i = 1; i < pq.length; i++) StdOut.print(pq[i] + " "); } public static void main(String[] args) { Integer[] a = {1,3,2,4,8,5,6,9,7}; MaxPQ<Integer> pq = new MaxPQ<Integer>(a); pq.show(); } }
标签:没有 oid rabl items while tom 2.4.1 show stat
原文地址:https://www.cnblogs.com/w-j-c/p/9141375.html