Ex: Run::posicaoMaiorRepeticao(‘ccddddeee') should return 2, since dddd is the longest repetition and its initial index is 2.
I got here, but the main function still could not do:
class Run
{
public static function posicaoMaiorRepeticao($str)
{
throw new Exception(‘Implementar’);
}
}
echo Run:: posicaoMaiorRepeticao('abbcccddddeeeeeefffffffffggg');
// 16
echo Run:: posicaoMaiorRepeticao('ddddeeeeeefffffffffgggggggggggggggggghhhhh’);
// 19
This does not work with multibyte characters!
In the post condition could simply do:
$string = 'ddddeeeeeefffffffffgggggggggggggggggghhhhh';
$QntPorCaractere = count_chars($string, 1);
arsort($QntPorCaractere);
reset($QntPorCaractere);
echo strpos($string, key($QntPorCaractere));
This will return the position of the first one of the most repeating letter in the string. That is, if it is gabcdefggg it would be 0 , because g is the one that repeats the most and the first position of g is 0 .
The count_chars using the 1 parameter will return exactly the number of occurrences (in the value) and what was the character (in the key) of the array, that is:
array(5) {
[100]=>
int(4)
[101]=>
int(6)
[102]=>
int(9)
[103]=>
int(18)
[104]=>
int(5)
}
In this case, the 103 is the g , in the ASCII table, so we can sort, after all we want the one that has more occurrences, we use arsort() .
Then we get the 103 , which is contained in the array key using key($QntPorCaractere) and we use it inside the strpos() that takes the first occurrence.
It may seem wrong to use strpos($string, 103); instead of using something like strpos($string, pack('C', 103)); . But the PHP manual says "If needle is not a string, it is converted to an integer and applied to the ordinal value of a character.", So since it is in the int format the 103 passes to g internally by strpos .
I do not know if there is any function of php to do this in a more practical way, but I did a very simple algorithm that does this:
<?php
function posicaoMaiorRepeticao($x)
{
$index = -1;
for ($i=0;$i<strlen($x);$i++)
{
if ($ultimo != $x[$i])
{
$ultimocount = $count;
$count = 0;
$ultimo = $x[$i];
}
else
{
$count++;
if ($count > $ultimocount)
$index = strpos($x, $x[$i]);
}
}
return $index;
}
$n = "abbcccddddeeeeeefffffffffggg";
echo posicaoMaiorRepeticao($n); //Output: 16
See working at Ideone .