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JavaScript數(shù)據(jù)結(jié)構(gòu)之單鏈表和循環(huán)鏈表

更新時間：2017年11月28日 11:44:39 作者：貳拾肆樵

這篇文章主要介紹了JavaScript數(shù)據(jù)結(jié)構(gòu)之單鏈表、循環(huán)鏈表，詳細的介紹了JavaScript如何實現(xiàn)單鏈表、循環(huán)鏈表，有興趣的可以了解一下

數(shù)據(jù)結(jié)構(gòu)系列前言：

數(shù)據(jù)結(jié)構(gòu)作為程序員的基本知識，需要我們每個人牢牢掌握。近期我也展開了對數(shù)據(jù)結(jié)構(gòu)的二次學習，來彌補當年挖的坑。。。。。。當時上課的時候也就是跟著聽課，沒有親自實現(xiàn)任何一種數(shù)據(jù)結(jié)構(gòu)，更別提利用數(shù)據(jù)結(jié)構(gòu)來解決問題了。現(xiàn)在就來填坑了奮斗在這里提醒看到我博客的孩子們，如果你還是在校生，永遠不要輕視任何一門基礎(chǔ)課的學習，這個時候挖的坑，要么需要用雙倍的努力去填，要么會直接影響一個人的能力等等。。。。。。千萬別給自己挖坑

進入正題，關(guān)于鏈表的數(shù)據(jù)結(jié)構(gòu)知識，這里簡單介紹下：

鏈表是一種物理存儲單元上非線性、非連續(xù)性的數(shù)據(jù)結(jié)構(gòu)（它在數(shù)據(jù)邏輯上是線性的），它的每個節(jié)點由兩個域組成：數(shù)據(jù)域和指針域。數(shù)據(jù)域中存儲實際數(shù)據(jù)，指針域則存儲著指針信息，指向鏈表中的下一個元素或者上一個元素。正是由于指針的存在，鏈表的存儲在物理單元是非連續(xù)性的。

鏈表的優(yōu)點和缺點同樣明顯。和線性表相比，鏈表在添加和刪除節(jié)點上的效率更高，因為其只需要修改指針信息即可完成操作，而不像線性表（數(shù)組）那樣需要移動元素。同樣的，鏈表的長度在理論上也是無限的（在存儲器容量范圍內(nèi)），并可以動態(tài)變化長度，相比線性表優(yōu)勢很大。相應(yīng)的，由于線性表無法隨機訪問節(jié)點，只能通過指針順著鏈表進行遍歷查詢來訪問，故其訪問數(shù)據(jù)元素的效率比較低。

下面是JS部分

這里面封裝了的常用方法及描述：

方法	描述
append(element)	向鏈表尾部添加結(jié)點element
insert(position,element)	向位置position處插入結(jié)點element
removeAt(position)	按照索引值position刪除結(jié)點
remove(element)	搜索并刪除給定結(jié)點element
remove()	刪除鏈表中最后一個結(jié)點
indexOf(element)	查找并返回給定結(jié)點element的索引值
isEmpty()	判斷鏈表是否為空
size()	獲取鏈表長度
toString()	轉(zhuǎn)換為字符串輸出
getHead()	獲取頭結(jié)點
getTail()	獲取尾結(jié)點

對于各常用方法的算法描述在這里就不寫了，相信大家都可以輕易讀懂并理解，畢竟都是非常基礎(chǔ)的知識了。

單鏈表：

function LinkedList(){ 
 /*節(jié)點定義*/ 
 var Node = function(element){ 
  this.element = element; //存放節(jié)點內(nèi)容 
  this.next = null; //指針 
 } 
 
 var length = 0, //存放鏈表長度 
  head = null; //頭指針 
 
 this.append = function(element){ 
  var node = new Node(element), 
   current; //操作所用指針 
 
  if (!head){ 
   head = node; 
  }else { 
   current = head; 
 
   while(current.next){ 
    current = current.next; 
   } 
 
   current.next = node; 
  } 
 
  length++; 
  return true; 
 }; 
 
 this.insert = function(position, element){ 
  if (position >= 0 && position <= length) { 
   var node = new Node(element), 
    current = head, 
    previous, 
    index = 0; 
 
   if(position === 0){ 
    node.next = current; 
    head = node; 
   }else{ 
    while(index++ < position){ 
     previous = current; 
     current = current.next; 
    } 
    node.next = current; 
    previous.next = node; 
   } 
 
   length++; 
   return true; 
  }else{ 
   return false; 
  } 
  }; 
 
 this.removeAt = function(position){ 
  if(position > -1 && position < length){ 
   var current = head, 
    previous, 
    index = 0; 
 
   if (position === 0) { 
 
    head = current.next; 
 
   }else{ 
 
    while (index++ < position){ 
     previous = current; 
     current = current.next; 
    } 
 
    previous.next = current.next; 
   }; 
 
   length--; 
   return current.element; 
  }else{ 
   return null; 
  } 
 }; 
 
 this.remove = function(element){ 
  var current = head, 
   previous; 
 
  if(element === current.element){ 
   head = current.next; 
   length--; 
   return true; 
  } 
  previous = current; 
  current = current.next; 
 
  while(current){ 
   if(element === current.element){ 
    previous.next = current.next; 
    length--; 
    return true; 
   }else{ 
    previous = current; 
    current = current.next; 
   } 
  } 
  return false; 
 }; 
 
 this.remove = function(){ 
  if(length < 1){ 
   return false; 
  } 
 
  var current = head, 
  previous; 
 
  if(length == 1){ 
   head = null; 
   length--; 
   return current.element; 
  } 
 
  
  while(current.next !== null){ 
   previous = current; 
   current = current.next; 
  } 
 
  previous.next = null; 
  length--; 
  return current.element; 
 }; 
 
 this.indexOf = function(element){ 
  var current = head, 
   index = 0; 
 
  while(current){ 
   if(element === current.element){ 
    return index; 
   } 
   index++; 
   current = current.next; 
  } 
 
  return false; 
 }; 
 
 this.isEmpty = function(){ 
  return length === 0; 
 }; 
 
 this.size = function(){ 
  return length; 
 }; 
 
 this.toString = function(){ 
  var current = head, 
   string = ''; 
 
  while(current){ 
   string += current.element; 
   current = current.next; 
  } 
  return string; 
 };  
 
 this.getHead = function(){ 
  return head; 
 } 
  
}

循環(huán)鏈表：在單鏈表的基礎(chǔ)上，將尾節(jié)點的指針指向頭結(jié)點，就構(gòu)成了一個循環(huán)鏈表。環(huán)形鏈表從任意一個節(jié)點開始，都可以遍歷整個鏈表。

function CircularLinkedList(){ 
 var Node = function(element){ 
  this.element = element; 
  this.next = null; 
 } 
 
 var length = 0, 
  head = null; 
 
 this.append = function(element){ 
  var node = new Node(element), 
   current; 
 
  if (!head) { 
   head = node; 
   node.next = head; 
  }else{ 
   current = head; 
 
   while(current.next !== head){ 
    current = current.next; 
   } 
 
   current.next = node; 
   node.next = head; 
  }; 
 
  length++; 
  return true; 
 }; 
 
 this.insert = function(position, element){ 
  if(position > -1 && position < length){ 
   var node = new Node(element), 
    index = 0, 
    current = head, 
    previous; 
 
 
   if (position === 0) { 
 
    node.next = head; 
    head = node; 
 
   }else{ 
 
    while(index++ < position){ 
     previous = current; 
     current = current.next; 
    } 
 
    previous.next = node; 
    node.next = current; 
 
   }; 
 
   length++; 
   return true; 
  }else{ 
   return false; 
  } 
 }; 
 
 this.removeAt = function(position){ 
  if(position > -1 && position < length){ 
   var current = head, 
    previous, 
    index = 0; 
 
   if (position === 0) { 
 
    head = current.next; 
 
   }else{ 
 
    while (index++ < position){ 
     previous = current; 
     current = current.next; 
    } 
 
    previous.next = current.next; 
   }; 
 
   length--; 
   return current.element; 
  }else{ 
   return null; 
  } 
 }; 
 
 this.remove = function (element){ 
  var current = head, 
   previous, 
   indexCheck = 0; 
 
  while(current && indexCheck < length){ 
   if(current.element === element){ 
    if(indexCheck == 0){ 
     head = current.next; 
     length--; 
     return true; 
    }else{ 
     previous.next = current.next; 
     length--; 
     return true; 
    } 
   }else{ 
    previous = current; 
    current = current.next; 
    indexCheck++; 
   } 
  } 
  return false; 
 }; 
 
 this.remove = function(){ 
  if(length === 0){ 
   return false; 
  } 
 
  var current = head, 
   previous, 
   indexCheck = 0; 
 
  if(length === 1){ 
   head = null; 
   length--; 
   return current.element; 
  } 
 
  while(indexCheck++ < length){ 
   previous = current; 
   current = current.next; 
  } 
  previous.next = head; 
  length--; 
  return current.element; 
 }; 
 
 this.indexOf = function(element){ 
  var current = head, 
   index = 0; 
 
  while(current && index < length){ 
   if(current.element === element){ 
    return index; 
   }else{ 
    index++; 
    current = current.next; 
   } 
  } 
  return false; 
 }; 
 
 
 this.isEmpty = function(){ 
  return length === 0; 
 }; 
 
 this.size = function(){ 
  return length; 
 }; 
 
 this.toString = function(){ 
  var current = head, 
   string = '', 
   indexCheck = 0; 
 
  while(current && indexCheck < length){ 
   string += current.element; 
   current = current.next; 
   indexCheck++; 
  } 
 
  return string; 
 };  
 
}

使用方法：