/*** 实现在链表中向前移动n个节点和向后移动n个节点* * *///链表节点
function Node(element){this.element = element;this.next = null;this.previous = null;
}//链表
function LList(){this.head = new Node('head');this.find = find;this.insert = insert;this.display = display;this.remove = remove;this.findLast = findLast;this.dispReverse = dispReverse;//当前节点就是头节点this.currentNode = this.head;//从链表开头向前移动n个节点this.advance = advance;//从链表某个节点向后回退n个节点this.back = back;//显示当前节点this.show = show;
}//倒序输出链表中的所有节点
function dispReverse(){var currNode = this.head;currNode = this.findLast();while (!(currNode.previous == null)){document.write(currNode.element + ' ');currNode = currNode.previous;}
}//找到最后一个节点
function findLast(){var currNode = this.head;while (!(currNode.next == null)){currNode = currNode.next;}return currNode;
}//删除某一个节点
function remove(item){var currNode = this.find(item);if(!(currNode.next == null)){currNode.previous.next = currNode.next;currNode.next.previous = currNode.previous;currNode.next = null;currNode.previous = null;}
}//打印所有链表节点
function display(){var currNode = this.head;while (!(currNode.next == null)){document.write(currNode.next.element + ' ');currNode = currNode.next;}
}//找到某一个节点
function find(item){var currNode = this.head;while (currNode.element != item){currNode = currNode.next;}return currNode;
}//插入某一个节点
function insert(newElement , item){var newNode = new Node(newElement);var current = this.find(item);newNode.next = current.next;newNode.previous = current;current.next = newNode;
}//在链表中向前移动n个节点
function advance(n){while ((n>0) && !(this.currentNode.next==null)){this.currentNode = this.currentNode.next; n--}
}//在链表中向后移动n个节点
function back(n){while (n>0 && !(this.currentNode.element=='head')){this.currentNode = this.currentNode.previous;n--;}
}//显示当前节点
function show(){document.write(this.currentNode.element);
}var cities = new LList();
cities.insert('Conway','head');
cities.insert('Russellville', 'Conway');
cities.insert('Carlisle', 'Russellville');
cities.insert('Alma' , 'Carlisle');
cities.insert('dezhou' , 'Alma');
cities.insert('alasijia' , 'dezhou');
cities.display();
document.write('<br>');cities.show();
cities.advance(4);
document.write('<br>');
cities.show();
cities.back(2);
document.write('<br>');
cities.show();