这篇文章主要介绍了js神秘的电报密码 哈弗曼编码,文中通过示例代码介绍的非常详细，对大家的学习或者工作具有一定的参考学习价值,需要的朋友可以参考下
哈夫曼编码，根据每个单词在文本中出现的次数频率为权值，频率高的权值大。然后每次取两个频率最小的生成树，最后生成一颗大树。从根节点到该单词的路径，左边为0，右边为1,
function HFM(){ var souce = []; function createNode(node){ var obj = { weight:0, parent:-1, lchild:-1, rchild:-1, value:'' }; return Object.assign(obj,node); } this.addNode = function(node){ //添加单词和频率（权值） souce.push(createNode(node)); } this.createTree = function(){ //哈夫曼树 var HuffNode = JSON.parse(JSON.stringify(souce)); var n = HuffNode.length; var x1,x2; //两个权值最小的索引 var m1,m2; //两个权值最小的值 for(var i = 0; i < n ; i++){ m1 = m2 = Infinity; //初始化为最大值 x1 = x2 = -1; for(var j = 0; j < n+i; j++){ //寻找两个权值最小，且父节点为-1的 var item = HuffNode[j]; if(item.weight < m1 && item.parent == -1){ m2 = m1; x2 = x1; m1 = item.weight; x1 = j; }else if(item.weight < m2 && item.parent == -1){ m2 = item.weight;; x2 = j; } } if(x1 != -1 && x2 != -1){ HuffNode[x1].parent = n + i; //更新父节点 HuffNode[x2].parent = n + i; //创建一个新的节点 HuffNode[n+i] = createNode({ weight:m1+m2, lchild:x1, rchild:x2 }); } } return HuffNode; }; this.getCode = function(){ //哈夫曼编码 var n = souce.length; var tree = this.createTree(); var codes = {}; for(var i = 0; i < n; i++){ var p = tree[i].parent; var code = ''; var c = i; while(p != -1){ //迭代前溯 if(tree[p].lchild == c){ code = 0 + code; }else{ code = 1 + code; } c = p; p = tree[p].parent; } codes[ tree[i].value ] = code; console.log(tree[i].value , code); } return codes; } } var hfm = new HFM(); hfm.addNode({ weight:5, value:"a" }); hfm.addNode({ weight:32, value:"b" }); hfm.addNode({ weight:18, value:"c" }); hfm.addNode({ weight:7, value:"d" }); hfm.addNode({ weight:25, value:"e" }); hfm.addNode({ weight:13, value:"f" }); console.log(hfm.getCode())