代码如下:

package HuffmanTreeArrays;import java.util.ArrayList;
import java.util.Scanner;public class HuffmanTree {private class TreeNode{private int val;private int left;private int right;private int parent;public TreeNode(){val = 0;left = -1;right = -1;parent = -1;}public TreeNode(int e){val = e;left = -1;right = -1;parent = -1;}}private TreeNode data[];private int capacity;private int size;private final int maxData;public HuffmanTree(int n){maxData = 999999999;size = n;capacity = 2*n-1;data = new TreeNode[2*n];TreeNode t = new TreeNode(maxData);data[0] = t;Scanner sc = new Scanner(System.in);for (int i = 1;i<=n;i++){t = new TreeNode(sc.nextInt());data[i] = t;}}public void buildHuffmanTree(){int s1,s2;for (int i = size+1;i<=capacity;i++){s1 = s2 = 0;for (int j = 1;j<=i-1;j++){if (data[j].parent==-1) {if (data[j].val < data[s1].val) {s2 = s1;s1 = j;} else if (data[j].val < data[s2].val) {s2 = j;}}}data[s1].parent = i;data[s2].parent = i;TreeNode t = new TreeNode(data[s1].val+data[s2].val);t.left = s1;t.right = s2;data[i] = t;printNode(t);}}private void printNode(TreeNode t){System.out.println(t.val+" ("+data[t.left].val+","+data[t.right].val+")");}public void codeHuffmanTree(){if (size==0){System.out.println("The HuffmanTree is empty");return ;}ArrayList<Integer> arrays = new ArrayList<>();dfsTree(data[capacity],arrays);}private void dfsTree(TreeNode t,ArrayList<Integer> arrays){if (t.left==-1 && t.right==-1){System.out.println(t.val+" "+arrays);return ;}if (t.left!=-1){arrays.add(0);dfsTree(data[t.left],arrays);arrays.remove(arrays.lastIndexOf(0));}if (t.right!=-1){arrays.add(1);dfsTree(data[t.right],arrays);arrays.remove(arrays.lastIndexOf(1));}}}

测试类如下:

package HuffmanTreeArrays;public class TestHuffmanTree {public static void main(String[] args){HuffmanTree hf = new HuffmanTree(7);hf.buildHuffmanTree();hf.codeHuffmanTree();}
}