<?php
 
function unique($palavra){
	$p = str_split($palavra);
	return implode(array_map(function ($c) use ($p) { 
		              return ($c > 0 && $p[$c] == $p[$c - 1] ? '': $p[$c]); 
		           }, array_keys($p)));
}
 
 
echo unique("Banana") . "\n";        // Banana
echo unique("Arara") . "\n";         // Arara
echo unique("assassinos") . "\n";    // asasinos
echo unique("Marreco") . "\n";       // Mareco
echo unique("Elllizabettth") . "\n"; // Elizabeth
echo unique("FooBaaar") . "\n";      // FoBar
echo unique("Woow") . "\n";          // Wow
echo unique("baazz") . "\n";         // baz

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