saravankg - 9 months ago 27

PHP Question

I have an array like this:

`$arr = array(25, 30, 50, 15, 20, 30);`

I want to fetch all keys which values total comes to

`100`

`100`

`100`

I need the total 100 like

`> $array[2]+$array[4]+$array[5]=100`

My actual need is what combinations are comes to 100

Answer

Finally I got it. There might be better solutions, but it works ...

Your problem is complex. There are 720 possible unique permutation of an array with 6 entries. More entries means more combinations. So I first got all unique permuations and then calculate the possibilies below or equal hundred for each combination.

```
$array = array(25, 30, 50, 15, 20, 30);
// 'permutations' function can be found at the bottom of my post
$permutations = permutations(array_keys($array));
$combinations = array();
foreach( $permutations as $keys ) {
$current = array("sum" => 0, "keys" => array());
foreach( $keys as $key ) {
if( $current["sum"] + $array[$key] <= 100 ) {
$current["sum"] += $array[$key];
$current["keys"][] = $key;
}
}
// order the keys and create a hash of them
// to be sure each combination only exists once in the result
sort($current["keys"]);
$combinations[md5(join("", $current["keys"]))] = $current;
}
// remove the hashes from array when finished
$combinations = array_values($combinations);
// the final result
print_r($combinations);
```

For your array, there are 11 possible combinations. Result would be:

```
Array (
[0] => Array (
[sum] => 90
[keys] => Array (
[0] => 0
[1] => 1
[2] => 3
[3] => 4
)
)
[1] => Array (
[sum] => 90
[keys] => Array (
[0] => 0
[1] => 2
[2] => 3
)
)
[2] => Array (
[sum] => 95
[keys] => Array (
[0] => 1
[1] => 2
[2] => 3
)
)
[3] => Array (
[sum] => 95
[keys] => Array (
[0] => 0
[1] => 2
[2] => 4
)
)
[4] => Array (
[sum] => 100
[keys] => Array (
[0] => 1
[1] => 2
[2] => 4
)
)
[5] => Array (
[sum] => 85
[keys] => Array (
[0] => 2
[1] => 3
[2] => 4
)
)
[6] => Array (
[sum] => 100
[keys] => Array (
[0] => 0
[1] => 1
[2] => 3
[3] => 5
)
)
[7] => Array (
[sum] => 95
[keys] => Array (
[0] => 2
[1] => 3
[2] => 5
)
)
[8] => Array (
[sum] => 100
[keys] => Array (
[0] => 2
[1] => 4
[2] => 5
)
)
[9] => Array (
[sum] => 90
[keys] => Array (
[0] => 0
[1] => 3
[2] => 4
[3] => 5
)
)
[10] => Array (
[sum] => 95
[keys] => Array (
[0] => 1
[1] => 3
[2] => 4
[3] => 5
)
)
)
```

The used `permutations`

function is based on the php cookbook but changed four your need.

```
function permutations($items, $perms = array(), $result = array()) {
if( !empty($items) )
for( $i = count($items) - 1; $i >= 0; --$i ) {
$newItems = $items;
$newPerms = $perms;
list($values) = array_splice($newItems, $i, 1);
array_unshift($newPerms, $values);
if( count($newPerms) == 6 )
$result[md5(join("", $newPerms))] = $newPerms;
$result = permutations($newItems, $newPerms, $result);
}
return $result;
}
```