Lesson 3 – Prefix Sums – GenomicRangeQuery demo task solution code written in php. Gives 100/100 score at the time of publishing. The description of the problem is copyrighted, so please see the following link for it: https://codility.com/demo/take-sample-test/genomic_range_query
Solution in php:
function solution($S, $P, $Q) {
$S = str_split($S);
$len = count($S);
$lep = count($P);
$arr = array();
$result = array();
$clone = array_fill(0, 4, 0);
for($i = 0; $i < $len; $i++){
$arr[$i] = $clone;
switch($S[$i]){
case 'A':
$arr[$i][0] = 1;
break;
case 'C':
$arr[$i][1] = 1;
break;
case 'G':
$arr[$i][2] = 1;
break;
default:
$arr[$i][3] = 1;
break;
}
}
for($i = 1; $i < $len; $i++){
for($j = 0; $j < 4; $j++){
$arr[$i][$j] += $arr[$i - 1][$j];
}
}
for($i = 0; $i < $lep; $i++){
$x = $P[$i];
$y = $Q[$i];
for($a = 0; $a < 4; $a++){
$sub = 0;
if($x - 1 >= 0){
$sub = $arr[$x - 1][$a];
}
if($arr[$y][$a] - $sub > 0){
$result[$i] = $a + 1;
break;
}
}
}
return $result;
}
Given “AS IS”, can be ported from other languages from solutions found on the internet, please use with care.
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