how can a find multiple values at once in an array php - php

Question

trying to make a tic-tac-toe game actually. So if there's a better way I would like to know too!
So I have a grid [0,8], and the user's positions are stored in an array. Great.
Next I want to see if the columns match up. So let's say first row is (0,1,2).
My question is if the user has an array like array(1,5,6,0,2), so he won. How can I match it efficiently?
I was thinking of doing something like this but doesn't look efficient:
$user= array(1,5,6,0,2);
in_array(0,$user) && in_array(1,$user) && in_array(2,$user)
I also thought about switch case but still face the question how do I find multiple values at once.

Answer 1

I agree that with such a small number of possible combinations to win, the solution can be kept very simple. I would do it using array_diff.
function has_won($user) {
// returns false if the user has not won, otherwise
// returns the first winning combination found.
$wins = [[0,1,2],[3,4,5],[6,7,8],[0,3,6],[1,4,7],[2,5,8],[0,4,8],[2,4,6]];
foreach ($wins as $win) {
if (!array_diff($win, $user)) return $win;
// array_diff returns the values in the first argument
// not present in any subsequent arguments. So if its
// result is empty, the user has winning combination.
}
return false;
}

Answer 2

I will not make a claim that this is the most efficient method, but it reduces the number of operations considerably compared with && chaining and multiple in_array() calls.
What we'll do is keep a 2-dimensional array of possible win-combinations: rows, columns, diagonals, as sub-arrays. Then in a foreach loop over that 2D array, test the user's current array state against the row combination with array_intersect(). If the entire winning combination is present in the user's array, the result of array_intersect() will be 3, which you can test with count().
Since one match is enough for a win, you can break out of the loop on the first match to declare a win.
$combinations = array(
// Rows
array(0,1,2),
array(3,4,5),
array(6,7,8),
// Columns
array(0,3,6),
array(1,4,7),
array(2,5,8),
// Diagonals
array(0,4,8),
array(2,4,6),
);
// Loop over the array of winners and test array_intersect()
// If 3 values intersect, the full win combination was matched
foreach ($combinations as $combination) {
if (count(array_intersect($combination, $user)) == 3) {
// User wins! Take whatever action necessary...
// Exit the loop
break;
}
}
Here's a demonstration in which 2 of 3 sets for $user are winners: http://codepad.viper-7.com/Mvu0wa
There are algorithmic ways of generating the winning combinations rather than hard-coding them, but there are only eight possible combinations so it isn't that hard, and the point here is the use of array_intersect() to find a subset of the user's current placements.