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<?php $blue = array(1,4,7,10); $red = array(2,3,5,6,8,9); $final_array = array(); $j = 0; for($i=0; $i<sizeof($blue); $i++) { $final_array[] = $blue[$i]; $r = $i*2; $p = $r+1; $final_array[] = $red[$r]; $final_array[] = $red[$p]; } echo '<pre>'; print_r($final_array);

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40.08 ms | 402 KiB | 5 Q