本文实例讲述了JS实现的哈夫曼编码。分享给大家供大家参考，具体如下：
原始版
404_6@ y.data.val});
}
function Node(left,right,data) {
this.left = left;
this.right = right;
this.data = data;
}
function makeTree(table) {
var i = 0;
var len = table.length;
var node1;
var node2;
var parentNode;
while(table.length > 1) {
parentNode = new Node(table[i],table[i+1],{key: null,val: table[i]['data'].val + table[i+1]['data'].val});
table.splice(i,2);
table.unshift(parentNode);
table.sort(function(x,y){return x.data.val > y.data.val});
}
return table;
}
function encode(str,ret) {
if (typeof str !== 'string' || str.length < 1) {
return;
}
var i = 0;
var result = '';
while(str[i]) {
result += ret[str[i++]];
}
return result
}
function reverseRet(ret) {
var result = {};
for (key in ret) {
if(ret.hasOwnProperty(key)) {
result[ret[key]] = key;
}
}
return result;
}
function decode(str,ret) {
var i = 0;
var result = '';
var data = '';
var map = reverseRet(ret);
while(str) {
result += str[i++];
if (result in map) {
data += map[result];
str = str.replace(new RegExp("^"+result),'');
result = '';
i = 0;
}
}
console.log(data)
}
function traversal(tree,code,ret) {
if (tree.left !== null) {
traversal(tree.left,code + '0',ret);
} else {
ret[tree.data.key] = code;
}
if (tree.right !== null) {
traversal(tree.right,code + '1',ret);
} else {
ret[tree.data.key] = code;
}
}
var ret = {};
var str = 'ew qew qd ef 24 gf ewr getElementsByTagName';
traversal(makeTree(sort(cal(str)))[0],'',ret)
decode(encode(str,ret),ret)
btoa(encode(str,ret))
修改版
1) {
parentNode = new Node(table[i],y){return x.data.val > y.data.val});
}
this.root = table[0] || new Node();
return this.root;
}
Huffman.prototype.traversal = function traversal(tree,code) {
if (tree.left !== null) {
traversal.call(this,tree.left,code + '0');
} else {
this.keyCodeMap[tree.data.key] = code;
}
if (tree.right !== null) {
traversal.call(this,tree.right,code + '1');
} else {
this.keyCodeMap[tree.data.key] = code;
}
}
Huffman.prototype.encode = function encode() {
this.cal();
this.sort();
var root = this.makeTree();
this.traversal(root,'');
var ret = this.keyCodeMap;
var i = 0;
var result = '';
var str = this.str;
while(str[i]) {
result += ret[str[i++]];
}
this.code = result;
console.log('encode:' + result);
return result
}
Huffman.prototype.reverseMap = function reverseMap() {
var ret = this.keyCodeMap;
var result = {};
for (key in ret) {
if(ret.hasOwnProperty(key)) {
result[ret[key]] = key;
}
}
this.codeKeyMap = result;
return result;
}
Huffman.prototype.decode = function decode() {
var i = 0;
var result = '';
var data = '';
var map = this.reverseMap();
var str = this.code;
while(str) {
result += str[i++];
if (result in map) {
data += map[result];
str = str.replace(new RegExp("^"+result),'');
result = '';
i = 0;
}
}
console.log("decode:" + data)
}
Huffman.prototype.encodeBase64 = function() {
try {
var base64 = btoa(this.code);
return base64;
} catch(e) {
return '';
}
}
var str = 'ew qew qd ef 24 gf ewr getElementsByTagName';
var huffman = new Huffman(str)
huffman.encode(str)
huffman.decode();
huffman.encodeBase64();
更多关于JavaScript相关内容感兴趣的读者可查看本站专题：《》、《》、《》、《》、《》及《》
希望本文所述对大家JavaScript程序设计有所帮助。
原文链接：https://www.f2er.com/js/32673.html