PHP-da ortiqcha sikl aylanishlarini optimallashtirish

Quyidagi kodda ma'lum bir dasturchi massivda 3 soni bormi yo'qmi tekshiradi:

php<?php
  $arr = [1, 2, 3, 4, 5, 6, 7, 8, 9];
  
  $exists = false;
  foreach ($arr as $elem) {
    if ($elem == 3) {
      $exists = true;
    }
  }
  
  var_dump($exists);
?>

Uning yechimi nima bilan noto'g'ri? Go'yo sikl ichida hech qanday ortiqcha amallar bajarilmayotgandek. Biroq, muammo shundaki, 3 soni massivda borligi aniqlandan so'ng - sikl baribir massiv oxirigacha aylanib turadi.

Eng noqulay holat, agar 3 soni massivning boshida topilsa, va massivning o'zi uzunligi, aytaylik, 1000 elementdan iborat bo'lsa. Natijada mingta foydasiz ortiqcha sikl aylanishlari bo'ladi! Optimal emas.

Kodni siklni o'z vaqtida to'xtatib optimallashtiramiz:

php<?php
  $arr = [1, 2, 3, 4, 5, 6, 7, 8, 9];
  
  $exists = false;
  foreach ($arr as $elem) {
    if ($elem == 3) {
      $exists = true;
      break;
    }
  }
  
  var_dump($exists);
?>

php<?php
  $arr = [1, 2, 3, 4, 5, 6, 7, 8, 9];
  $sum = 0;
  $i = 1;
  
  foreach ($arr as $elem) {
    $sum += $elem;
    
    if ($sum <= 10) {
      $i++;
    }
  }
  
  echo $i;
?>

php<?php
  for ($i = 0; $i <= 100; $i++) {
    if ($i % 2 === 0) {
      echo $i;
    }
  }
?>

php<?php
  for ($i = 0; $i <= 100; $i++) {
    if ($i % 2 === 0 and $i % 3 === 0) {
      echo $i;
    }
  }
?>