// by 司徒正美
class Trie {
 constructor() {
  this.root = new TrieNode();
 }
 isValid(str) {
  return /^[a-z1-9]+$/i.test(str);
 }
 insert(word) {
  // addWord
  if (this.isValid(word)) {
   var cur = this.root;
   for (var i = 0; i < word.length; i++) {
    var c = word.charCodeAt(i);
    c -= 48; //減少”0“的charCode
    var node = cur.son[c];
    if (node == null) {
     var node = (cur.son[c] = new TrieNode());
     node.value = word.charAt(i);
     node.numPass = 1; //有N個(gè)字符串經(jīng)過它
    } else {
     node.numPass++;
    }
    cur = node;
   }
   cur.isEnd = true; //檣記有字符串到此節(jié)點(diǎn)已經(jīng)結(jié)束
   cur.numEnd++; //這個(gè)字符串重復(fù)次數(shù)

   return true;
  } else {
   return false;
  }
 }
 remove(word){
   if (this.isValid(word)) {
     var cur = this.root;
     var array = [], n = word.length
     for (var i = 0; i < n; i++) {
       var c = word.charCodeAt(i);
       c = this.getIndex(c)
       var node = cur.son[c];
       if(node){
         array.push(node)
         cur = node
       }else{
         return false
       }
 
     }
     if(array.length === n){
       array.forEach(function(){
         el.numPass--
       })
       cur.numEnd --
       if( cur.numEnd == 0){
         cur.isEnd = false
       } 
     }
   }else{
     return false
   }
 }
 preTraversal(cb){//先序遍歷
    function preTraversalImpl(root, str, cb){ 
      cb(root, str);
      for(let i = 0,n = root.son.length; i < n; i ++){
        let node = root.son[i];
        if(node){
          preTraversalImpl(node, str + node.value, cb);
        }
      }
    } 
    preTraversalImpl(this.root, "", cb);
  }
 // 在字典樹中查找是否存在某字符串為前綴開頭的字符串(包括前綴字符串本身)
 isContainPrefix(word) {
  if (this.isValid(word)) {
   var cur = this.root;
   for (var i = 0; i < word.length; i++) {
    var c = word.charCodeAt(i);
    c -= 48; //減少”0“的charCode
    if (cur.son[c]) {
     cur = cur.son[c];
    } else {
     return false;
    }
   }
   return true;
  } else {
   return false;
  }
 }
 isContainWord(str) {
  // 在字典樹中查找是否存在某字符串(不為前綴)
  if (this.isValid(word)) {
   var cur = this.root;
   for (var i = 0; i < word.length; i++) {
    var c = word.charCodeAt(i);
    c -= 48; //減少”0“的charCode
    if (cur.son[c]) {
     cur = cur.son[c];
    } else {
     return false;
    }
   }
   return cur.isEnd;
  } else {
   return false;
  }
 }
 countPrefix(word) {
  // 統(tǒng)計(jì)以指定字符串為前綴的字符串?dāng)?shù)量
  if (this.isValid(word)) {
   var cur = this.root;
   for (var i = 0; i < word.length; i++) {
    var c = word.charCodeAt(i);
    c -= 48; //減少”0“的charCode
    if (cur.son[c]) {
     cur = cur.son[c];
    } else {
     return 0;
    }
   }
   return cur.numPass;
  } else {
   return 0;
  }
 }
 countWord(word) {
  // 統(tǒng)計(jì)某字符串出現(xiàn)的次數(shù)方法
  if (this.isValid(word)) {
   var cur = this.root;
   for (var i = 0; i < word.length; i++) {
    var c = word.charCodeAt(i);
    c -= 48; //減少”0“的charCode
    if (cur.son[c]) {
     cur = cur.son[c];
    } else {
     return 0;
    }
   }
   return cur.numEnd;
  } else {
   return 0;
  }
 }
}

class TrieNode {
 constructor() {
  this.numPass = 0;//有多少個(gè)單詞經(jīng)過這節(jié)點(diǎn)
  this.numEnd = 0; //有多少個(gè)單詞就此結(jié)束
  this.son = [];
  this.value = ""; //value為單個(gè)字符
  this.isEnd = false;
 }
}

// by 司徒正美
getIndex(c){
   if(c < 58){//48-57
     return c - 48
   }else if(c < 91){//65-90
     return c - 65 + 11
   }else {//> 97 
     return c - 97 + 26+ 11
   }
 }

var trie = new Trie(); 
  trie.insert("I"); 
  trie.insert("Love"); 
  trie.insert("China"); 
  trie.insert("China"); 
  trie.insert("China"); 
  trie.insert("China"); 
  trie.insert("China"); 
  trie.insert("xiaoliang"); 
  trie.insert("xiaoliang"); 
  trie.insert("man"); 
  trie.insert("handsome"); 
  trie.insert("love"); 
  trie.insert("Chinaha"); 
  trie.insert("her"); 
  trie.insert("know"); 
  var map = {}
  trie.preTraversal(function(node, str){
    if(node.isEnd){
     map[str] = node.numEnd
    }
  })
  for(var i in map){
    console.log(i+" 出現(xiàn)了"+ map[i]+" 次")
  }
  console.log("包含Chin（包括本身）前綴的單詞及出現(xiàn)次數(shù)："); 
  //console.log("China")
  var map = {}
  trie.preTraversal(function(node, str){
    if(str.indexOf("Chin") === 0 && node.isEnd){
      map[str] = node.numEnd
    }
   })
  for(var i in map){
    console.log(i+" 出現(xiàn)了"+ map[i]+" 次")
  }