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Rewrote the linked list to not use Object.extend.
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@bramstein
bramstein committed Nov 22, 2011
1 parent 61b4ada commit 01e0755
Showing 1 changed file with 177 additions and 184 deletions.
361 changes: 177 additions & 184 deletions src/linked-list.js
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Original file line number Diff line number Diff line change
Expand Up @@ -4,187 +4,180 @@ function LinkedList() {
this.tail = null;
this.listSize = 0;
}
(function () {
Object.extend(LinkedList, {
Node: function (data) {
this.prev = null;
this.next = null;
this.data = data;
}
});

Object.extend(LinkedList.Node.prototype, {
toString: function () {
return this.data.toString();
}
});

function isLinked(list, node) {
return !((node && node.prev === null && node.next === null && list.tail !== node && list.head !== node) || list.isEmpty());
}

Object.extend(LinkedList.prototype, {
size: function () {
return this.listSize;
},

isEmpty: function () {
return this.listSize === 0;
},

first: function () {
return this.head;
},

last: function () {
return this.last;
},

toString: function () {
return this.toArray().toString();
},

toArray: function () {
var node = this.head,
result = [];
while (node !== null) {
result.push(node);
node = node.next;
}
return result;
},

// Note that modifying the list during
// iteration is not safe.
forEach: function (fun) {
var node = this.head;
while (node !== null) {
fun(node);
node = node.next;
}
},

contains: function (n) {
var node = this.head;
if (!isLinked(this, n)) {
return false;
}
while (node !== null) {
if (node === n) {
return true;
}
node = node.next;
}
return false;
},

at: function (i) {
var node = this.head, index = 0;

if (i >= this.listLength || i < 0) {
return null;
}

while (node !== null) {
if (i === index) {
return node;
}
node = node.next;
index += 1;
}
return null;
},

insertAfter: function (node, newNode) {
if (!isLinked(this, node)) {
return this;
}
newNode.prev = node;
newNode.next = node.next;
if (node.next === null) {
this.tail = newNode;
} else {
node.next.prev = newNode;
}
node.next = newNode;
this.listSize += 1;
return this;
},

insertBefore: function (node, newNode) {
if (!isLinked(this, node)) {
return this;
}
newNode.prev = node.prev;
newNode.next = node;
if (node.prev === null) {
this.head = newNode;
} else {
node.prev.next = newNode;
}
node.prev = newNode;
this.listSize += 1;
return this;
},

push: function (node) {
if (this.head === null) {
this.unshift(node);
} else {
this.insertAfter(this.tail, node);
}
return this;
},

unshift: function (node) {
if (this.head === null) {
this.head = node;
this.tail = node;
node.prev = null;
node.next = null;
this.listSize += 1;
} else {
this.insertBefore(this.head, node);
}
return this;
},

remove: function (node) {
if (!isLinked(this, node)) {
return this;
}
if (node.prev === null) {
this.head = node.next;
} else {
node.prev.next = node.next;
}
if (node.next === null) {
this.tail = node.prev;
} else {
node.next.prev = node.prev;
}
this.listSize -= 1;
return this;
},

pop: function () {
var node = this.tail;
this.tail.prev.next = null;
this.tail = this.tail.prev;
this.listSize -= 1;
node.prev = null;
node.next = null;
return node;
},

shift: function () {
var node = this.head;
this.head.next.prev = null;
this.head = this.head.next;
this.listSize -= 1;
node.prev = null;
node.next = null;
return node;
}
});
}());

LinkedList.Node = function (data) {
this.prev = null;
this.next = null;
this.data = data;
};

LinkedList.Node.prototype.toString = function () {
return this.data.toString();
};

LinkedList.prototype.isLinked = function (node) {
return !((node && node.prev === null && node.next === null && this.tail !== node && this.head !== node) || this.isEmpty());
};

LinkedList.prototype.size = function () {
return this.listSize;
};

LinkedList.prototype.isEmpty = function () {
return this.listSize === 0;
};

LinkedList.prototype.first = function () {
return this.head;
};

LinkedList.prototype.last = function () {
return this.last;
};

LinkedList.prototype.toString = function () {
return this.toArray().toString();
};

LinkedList.prototype.toArray = function () {
var node = this.head,
result = [];
while (node !== null) {
result.push(node);
node = node.next;
}
return result;
};

// Note that modifying the list during
// iteration is not safe.
LinkedList.prototype.forEach = function (fun) {
var node = this.head;
while (node !== null) {
fun(node);
node = node.next;
}
};

LinkedList.prototype.contains = function (n) {
var node = this.head;
if (!this.isLinked(n)) {
return false;
}
while (node !== null) {
if (node === n) {
return true;
}
node = node.next;
}
return false;
};

LinkedList.prototype.at = function (i) {
var node = this.head, index = 0;

if (i >= this.listLength || i < 0) {
return null;
}

while (node !== null) {
if (i === index) {
return node;
}
node = node.next;
index += 1;
}
return null;
};

LinkedList.prototype.insertAfter = function (node, newNode) {
if (!this.isLinked(node)) {
return this;
}
newNode.prev = node;
newNode.next = node.next;
if (node.next === null) {
this.tail = newNode;
} else {
node.next.prev = newNode;
}
node.next = newNode;
this.listSize += 1;
return this;
};

LinkedList.prototype.insertBefore = function (node, newNode) {
if (!this.isLinked(node)) {
return this;
}
newNode.prev = node.prev;
newNode.next = node;
if (node.prev === null) {
this.head = newNode;
} else {
node.prev.next = newNode;
}
node.prev = newNode;
this.listSize += 1;
return this;
};

LinkedList.prototype.push = function (node) {
if (this.head === null) {
this.unshift(node);
} else {
this.insertAfter(this.tail, node);
}
return this;
};

LinkedList.prototype.unshift = function (node) {
if (this.head === null) {
this.head = node;
this.tail = node;
node.prev = null;
node.next = null;
this.listSize += 1;
} else {
this.insertBefore(this.head, node);
}
return this;
};

LinkedList.prototype.remove = function (node) {
if (!this.isLinked(node)) {
return this;
}
if (node.prev === null) {
this.head = node.next;
} else {
node.prev.next = node.next;
}
if (node.next === null) {
this.tail = node.prev;
} else {
node.next.prev = node.prev;
}
this.listSize -= 1;
return this;
};

LinkedList.prototype.pop = function () {
var node = this.tail;
this.tail.prev.next = null;
this.tail = this.tail.prev;
this.listSize -= 1;
node.prev = null;
node.next = null;
return node;
};

LinkedList.prototype.shift = function () {
var node = this.head;
this.head.next.prev = null;
this.head = this.head.next;
this.listSize -= 1;
node.prev = null;
node.next = null;
return node;
};

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