// source http://jsbin.com/hetuza

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<html>
<head>
  <meta charset="utf-8">
  <title>JS Bin</title>
</head>
<body>

BinaryHeap.prototype = {
  
  push : function (element) {
      //if non js code do array resizing if array is full
      this._content.push(element);
      this.swim(this._content.length - 1);
  },
  size : function () {
    return this._content.length;
  },
  pop : function () {
      //if empty throw error
      if ( typeof this._content === 'undefined' ||
        this._content.length <= 0) throw new Error('the heap does not exist or is empty');
      var result = this._content[0];
        // if length is 1 then pop and that is it
      this.swap(0, this._content.length - 1);
      this._content.pop();
      if (this._content.length > 0) {
        this.sink(this._content[0]); 
      }
    return result;
  },
  compare: function (n1,n2) {
      var a = this._content[n1];
      var b = this._content[n2];
      if (typeof a !== 'number') a = Number(a);
      if (typeof b !== 'number') b = Number(b);
      if (a < b) return -1;
      else if ( a == b) return 0;
      else return 0;
  },
  swap : function (n1, n2) {
    var temp = this._content[n1];
    this._content[n1] = this._content[n2];
    this._content[n2] = temp;
  },
  swim : function (n) {
    // should do type checking
    while ( n >= 0 && this.compare(n, Math.floor(n/2)) >= 0) {
      this.swap(n, Math.floor(n/2));
      n = Math.floor(n/2);
    }
  },
  sink : function (n) {
    var childIndex; 
    while ( 2 * n <= this._content.length - 1) {
      childIndex = 2 * n;
      if (  childIndex < this._content.length && this.compare(childIndex, childIndex + 1)  < 0) 
      childIndex += 1;
      this.swap(n, childIndex);
      n = childIndex;
    }
  }
};
</script>