I have found myself writing a program the needs getting at hand a whole range of binomial coefficients from C(0,0) to C(n,m) for some given values of n and m.
In this case the most efficient way to get them is by using the Pascal’s triangle (triangolo di Tartaglia, in Italy).
I wrote this java class that implements it, with a few optimizations to avoid storing obvious values.
Each coefficient is stored as a BigInteger.
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I’ve just found the my website has been hacked.
I’ve found a new directory “guiex” (but the name can change) containing two files: “m” a text file just listing “index.php” and a php file named “mnq.php” (the code of this file is at the end of this post).
Now we have two questions to answer:
1) How the hell these files have arrived here?
2) What the f**k are these files doing here?
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What happens if a browser loads an HTML page like this one?
<html> <head> <title>Test 1</title> <script language="JavaScript"> while(true); </script> </head> <body> </body> </html>
Or this one?
<html>
<head>
<title>Test 2</title>
<script language="JavaScript">
while(true)
alert("free porn movies one click ahead 
");
</script>
</head>
<body>
</body>
</html>
Or this one?
<html>
<head>
<title>Test 3</title>
<script language="JavaScript">
var x = new Array();
var y = x;
while(true) {
y[0] = new Array();
y = y[0];
}
</script>
</head>
<body>
</body>
</html>
In the previous post I have discussed a typical case in which the use of a heap structure is very useful, presenting some code that allows to build and manage a heap structure on-top of a vector.
To complete the discussion this time I’m posting the C# code that implements a “clean” heap data structure. Continue reading
I this thread I will discuss about making order in our life… well… at least in a long vector of objects… OK, just a small part of that vector.
This is a fundamental aspect of search engines: you are interested in getting only the k most relevant results, whatever the size of the collection you are searching on is.
The k value is usually very small with respect to the collection size, e.g. on the Web one is likely to look at just the first ten-twenty results. Search engines typically set a z value of maximum returned results that is designed to be larger than the largest part of possible k values, e.g. Google returns at most one thousand results.
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