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我是新來的java，我想通過在線使用代碼來理解哈夫曼編碼。我搞亂了代碼來理解它是如何工作的，因爲我沒有發現如何實現霍夫曼代碼。 我需要理解爲什麼在這段代碼中，這個人在霍夫曼樹類和字符串緩衝區中使用可比。 如果有人知道在線霍夫曼編碼甚至算法的任何好解釋，請。 我真的需要了解這段代碼。 PS：英語不是我的母語，所以很抱歉有任何混淆。 謝謝霍夫曼代碼解釋Java
import java.util.*;
public class HuffmanCode {
// input is an array of frequencies, indexed by character code
public HuffmanTree buildTree(int[] charFreqs) {
PriorityQueue<HuffmanTree> trees = new PriorityQueue<HuffmanTree>();
// initially, we have a forest of leaves
// one for each non-empty character
for (int i = 0; i < charFreqs.length; i++)
if (charFreqs[i] > 0)
trees.offer(new HuffmanLeaf(charFreqs[i], (char)i));
assert trees.size() > 0;
// loop until there is only one tree left
while (trees.size() > 1) {
// two trees with least frequency
HuffmanTree a = trees.poll();
HuffmanTree b = trees.poll();
// put into new node and re-insert into queue
trees.offer(new HuffmanNode(a, b));
}
return trees.poll();
}
public void printCodes(HuffmanTree tree, StringBuffer prefix) {
assert tree != null;
if (tree instanceof HuffmanLeaf) {
HuffmanLeaf leaf = (HuffmanLeaf)tree;
// print out character, frequency, and code for this leaf (which is just the prefix)
System.out.println(leaf.value + "\t" + leaf.frequency + "\t" + prefix);
} else if (tree instanceof HuffmanNode) {
HuffmanNode node = (HuffmanNode)tree;
// traverse left
prefix.append('0');
//prefix = prefix + "0";
printCodes(node.left, prefix);
prefix.deleteCharAt(prefix.length()-1);
// traverse right
prefix.append('1');
printCodes(node.right, prefix);
prefix.deleteCharAt(prefix.length()-1);
}
}
}
哈夫曼樹類：
public class HuffmanTree implements Comparable<HuffmanTree> {
public final int frequency; // the frequency of this tree
public HuffmanTree(int freq) {
frequency = freq;
}
// compares on the frequency
public int compareTo(HuffmanTree tree) {
return frequency - tree.frequency;
}
}
霍夫曼葉：
class HuffmanLeaf extends HuffmanTree {
public final char value; // the character this leaf represents
public HuffmanLeaf(int freq, char val) {
super(freq);
value = val;
}
}
霍夫曼節點：
class HuffmanNode extends HuffmanTree {
public final HuffmanTree left, right; // subtrees
public HuffmanNode(HuffmanTree l, HuffmanTree r) {
//Calling the super constructor HuffmanTree
super(l.frequency + r.frequency);
left = l;
right = r;
}
}
主營：
public class Main {
public static void main(String[] args) {
String test = "Hello World";
HuffmanCode newCode = new HuffmanCode();
// we will assume that all our characters will have
// code less than 256, for simplicity
int[] charFreqs = new int[256];
// read each character and record the frequencies
for (char c : test.toCharArray())
charFreqs[c]++;
// build tree
////HuffmanTree tree = buildTree(charFreqs);
HuffmanTree tree = newCode.buildTree(charFreqs);
// print out results
System.out.println("SYMBOL\tWEIGHT\tHUFFMAN CODE");
newCode.printCodes(tree, new StringBuffer());
}
}
將打印語句添加到代碼或使用調試器並逐行運行，直到您認爲您明白 –
有人可以解釋我爲什麼這個人使用Stringbuffer和可比較的嗎？ –
不應該使用Stackoverflow作爲社區努力來理解您發現的一些隨機代碼，對不起。請嘗試運行代碼並找出它 –