<?php
//palavras chaves:
//Similarity Detection e Plagiarism Detector
 
//referencia:
//http://stackoverflow.com/questions/1085048/how-would-you-code-an-anti-plagiarism-site
 
function ncd($x, $y) { 
  $cx = strlen(gzcompress($x));
  $cy = strlen(gzcompress($y));
  return (strlen(gzcompress($x . $y)) - min($cx, $cy)) / max($cx, $cy);
}   
 
print "<br><br>0- ";
print(ncd('this', 'this'));
print "<br><br>1- ";
print(ncd('this is a test', 'this is a test'));
print "<br><br>2- ";
print(ncd('this is a test', 'this was a test'));
print "<br><br>3- ";
print(ncd('this is a test', 'this text is completely different'));
print "<br><br>4- ";
print(ncd('this is a test', 'nao tem nada haver!!!'));
 
print "<br><br>5- ";
print(ncd('this is a test', 'nao tem nada haver!!! nao tem nada haver!!! nao tem nada haver!!! nao 
 
tem nada haver!!!nada haver!!! nao tem nada haver!!!nada haver!!! nao tem nada haver!!!'));
 
print "<br>--------------------<br>6- ";
print(ncd('this is a test', 'nao tem nada haver!!! nao tem nada haver!!! nao tem nada haver!!! nao 
 
tem nada haver!!! this is a test'));
 
 
print "<br>--------------------<br>7- ";
print(ncd('this is a test', 'this is a test  this is a test  this is a test this is a test'));
 
print "<br>--------------------<br>8- ";
print(ncd('this is a test', 'a a a a'));
 
 
 
?>

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