pomelo-collection

Pomelo-collection is the module for basic data structure in Node.JS. The prefix 'pomelo' means the module is build for the open source game server framework pomelo.

Current the implemention data struction is priorityQueue and queue, more data structure will be added as need.

Installation

npm install pomelo-collection

How to Use

Use PriorityQueue

    var coll = require('pomelo-collection');
    
    //Use priorityQueue
    var PriorityQueue = coll.priorityQueue;
    
    //var comparator = function(a, b){
        return a > b;
    }
    
    //build a priority queue with custom comparator
    var pq = new PriorityQueue(comparator);
    
    //Use offer to add element to priorityQueue
    pq.offer(1);
    pq,offer(2);
    pq.offer(3);
    
    //Peek will get the element but not remove it, in this case, it will print 3 on the console.
    console.log(pq.peek());
    
    //pq will get and remove the top element in priorityQueue. In this case, it will print 3, 2, 1.
    while(pq.size()>0){
        console.log(pq.pop());
    }
    

The comparator is not necessary and can be omitted, a default comparator will be used if no comparator is offered, in fact the default comparator is the same as we used in the example. The priofityQueue is implement by an array, the cost of 'shift' and 'pop' are O(logN), where N is the element count in the priorityQueue, and the cost of 'peek' is O(1). The memory cost is O(N).

Use Queue

    var Queue = require('pomelo-collection').queue;
    
    //Construct a queue with size 10000
    var queue = new Queue(10000);
    
    //Use 'push' to add element
    queue.push(1);
    queue.push(2);
    queue.push(3);
    
    //Use 'pop' to remove element
    while(queue.size()>0){
        console.log(queue.pop());
    }

The Queue is implement with an array, the cost of 'push' , 'pop' and 'size' are all O(1). Push will fail if size exceed limit.