How to find count of non-unique elements of array in php using stdin for input

Question

following will be the input on STDIN.

The first line contains an integer, n, denoting the size of the numbers array.

Each line i of the n subsequent lines (where 0 ≤ i < n) contains an integer describing the value of numbers[i].

I want to print the integer denoting the number of non-unique values in numbers to STDOUT.

Sample Input

8 1 3 1 4 5 6 3 2

Sample Output

2

I have not worked with STDIN and STDOUT before so dont know how to use them. I know array_unique can solve my problem but i dont know how to read data through stdin and store it in an array — Jatin Purswani
– Jatin Purswani, Commented Feb 15, 2017 at 7:37

mith · Accepted Answer · 2017-02-15 08:00:29Z

1

Try using array_unique() and count() functions:

$array = [];
while ($in = fread(STDIN, 1024)) { 
   $array = array_merge($array, explode("\n", $in)); 
}

array_shift($array);

echo (count($array) - count(array_unique($array)));

edited Feb 15, 2017 at 8:00

answered Feb 15, 2017 at 7:31

mith

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9 Comments

Florian Schöffl Over a year ago

You need to remove the 8 from your array, because it is (like stated in the original problem) the length of the following integer sequence

Jatin Purswani Over a year ago

Thanks for your support. Highly appreciated. The problem is I know hwo to do this with array_unique and count but dont know how to read the data through STDIN and store it in the $array.

mith Over a year ago

use array_shift($array); to remove first element from array @FlorianSchöffl

mith Over a year ago

Try something like while ($in = fread(STDIN, 1024)) { $array = array_merge($array, explode("\n", $in)); } @JatinPurswani

Jatin Purswani Over a year ago

Thanks Mith. But this will take the first value of 8 as well in the array i guess?

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