day2-part1-Intcode-calendar

$opcodes = [1,12,2,3,1,1,2,3,1,3,4,3,1,5,0,3,2,9,1,19,1,19,6,23,2,6,23,27,2,27,9,31,1,5,31,35,1,35,10,39,2,39,9,43,1,5,43,47,2,47,10,51,1,51,6,55,1,5,55,59,2,6,59,63,2,63,6,67,1,5,67,71,1,71,9,75,2,75,10,79,1,79,5,83,1,10,83,87,1,5,87,91,2,13,91,95,1,95,10,99,2,99,13,103,1,103,5,107,1,107,13,111,2,111,9,115,1,6,115,119,2,119,6,123,1,123,6,127,1,127,9,131,1,6,131,135,1,135,2,139,1,139,10,0,99,2,0,14,0];

$i = 0;

do {
  $opcode = $opcodes[$i];

  switch ($opcode) {
      case 1:
        // add

        $pos1 = $opcodes[$i + 1];
        $pos2 = $opcodes[$i + 2];
        $pos3 = $opcodes[$i + 3];
        $opcodes[$pos3] = $opcodes[$pos1] + $opcodes[$pos2];

        break;
      case 2:
        // multiply

        $pos1 = $opcodes[$i + 1];
        $pos2 = $opcodes[$i + 2];
        $pos3 = $opcodes[$i + 3];
        $opcodes[$pos3] = $opcodes[$pos1] * $opcodes[$pos2];

        break;
  }

  $i += 4;

} while ($opcode != 99);

echo $opcodes[0];