另一个FizzBu​​zz解决方案[关闭]

I was in a job interview and was asked to solve FizzBuzz with PHP.

Write a program that prints the numbers from 1 to 100. But for multiples of three print “Fizz” instead of the number and for the multiples of five print “Buzz”. For numbers which are multiples of both three and five print “FizzBuzz”.

I never heard of FizzBuzz before but here is how I solved it:

for ($i = 1; $i <= 100; $i++){
   if($i / 3 == round($i / 3) && $i / 5 == round($i / 5)){
      echo $i . " is FizzBuzz<br />";
   }
   else if($i / 3 == round($i / 3)){
      echo $i . " is Fizz<br />";
   }
   else if($i / 5 == round($i / 5)){
      echo $i . " is Buzz<br />";
   }
   else {
      echo $i."<br />";
   }
}

I googled and didn't find any solution with round and that got me thinking that maybe there is something wrong with it, this is one of the solutions I found that is close to mine:

for ($i = 1; $i <= 100; $i++){
   if($i % 3 == 0 && $i % 5 ==0){
      echo "FizzBuzz<br />";
   }
   else if($i % 3 == 0){
      echo "Fizz<br />";
   }
   else if($i % 5 == 0){
      echo "Buzz<br />";
   }
   else {
      echo $i."<br />";
   }
}

My code is working fine but is there anything wrong with it that I don't see?

Actually they are testing how you will solve such simple task. It should be increadibly optimized, the code shouldbe clean and easy readable.

Your version of code is not good. The version you've found in the internet is better, but it's not ideal from the point of the optimization.

Try to think how to get the goal with less actions.

Some tips:

• do not use functions (such as range) for this task - it will only slow down the script execution time
• use operator "for" for this task, do not use any other (while, do-while, foreach), because operator "for" the best fits in this case (you know how many iterations you need).
• do not use round function, use modulus operator "%", because any function works slower than any operator

• in the result you need to get code, in which the number of operations will be the least as possible (the number of "if" statements, the number of operators like "==" or "%"

  • Use 15 instead of % 3 && % 5 - less calculations - faster execution time.

My example of code:

for ($i = 1; $i <= 100; $i++) {
    if ($i % 15 == 0) {
        echo 'FizzBuzz<br>';
    } elseif ($i % 3 == 0) {
        echo 'Fizz<br>';
    } elseif ($i % 5 == 0) {
        echo 'Buzz<br>';
    } else {
        echo $i . '<br>';
    }
}

if you read carefully it says "instead".

this is another short and clean solution of the FizzBuzz problem :

foreach (range(1, 100) as $number) {
    if(0 !== $number % 3 && 0 !== $number % 5) {
        echo $number.'<br>';
        continue;
    }

    if(0 === $number % 3) {
        echo 'Fizz';
    }

    if(0 === $number % 5) {
        echo 'Buzz';
    }

    echo '<br>';
}

the output is :

1
2
Fizz
4
Buzz
Fizz
7
8
Fizz
Buzz
11
Fizz
13
14
FizzBuzz
16

Code style and lack of optimization gives impression of a newbie to the interviewer. My tips are:

• Follow PSR-2
• Never use else (restructure, use early returns/continues)
• Always try to reduce the number of ifs (code complexity)
• Use "identical" operators for comparison when dealing with integers and nulls (and any other type)
• Do not use <br/> when HTML is never mentioned
• Try to keep maintainability:
  • Extract match calculations in variables/functions, so they can be easily changed
  • Do not overcomplicate.
• Try to optimize mathematically:
  • Use %15 instead of %3 and %5 check
  • You can also skip the above at all (check for %15), as you already have calculated that. Boolean operations are much faster.
  • Try not to calculate something twice.

IMHO, to follow all good practices your code should look like this:

for ($i = 1; $i <= 100; $i++) {
    $isFizz = (0 === $i % 3);
    $isBuzz = (0 === $i % 5);

    if (!$isFizz && !$isBuzz) {
        echo $i . PHP_EOL;

        continue;
    }

    if ($isFizz) {
        echo 'Fizz';
    }

    if ($isBuzz) {
        echo 'Buzz';
    }

    echo PHP_EOL;
}

Test

There is yet another tricky solution

for ($i = 1; $i <= 100; $i++) {
    switch ($i % 15) {
        case 3:
        case 6:
        case 9:
            echo 'Fizz';
            break;
        case 5:
        case 10:
            echo 'Buzz';
            break;
        case 0:
            echo 'FizzBuzz';
            break;
        default:
            echo $i;
            break;
    }

    echo PHP_EOL;
}