拆分数组但每个数组的总和不超过最大值,否则推送到下一个数组索引

I have two arrays, Array 1 being a donor array which has a series of values (not necessarily equal values as in my example). Array 2 is the desired result and would store a series of sub arrays with values from Array 1 where each sub array's total sum would not exceed 25. If it does, the excess would get pushed to the next index in Array 2 where the rules would also apply.

Donor array (Array 1):

$a1=array(10,10,10,10,10,10,10,10,10,10);

Desired output (Array 2):

Array
(
    [0] => 10,10,5
    [1] => 5,10,10
    [2] => 10,10,5
    [3] => 5,10,10
)

Here the code I tried but it gets an error:

Notice: Undefined offset: 10...etc.

$a1=array(10,10,10,10,10,10,10,10,10,10);
$a2=array();
$count=count($a1);

for($i=0;$i<$count;$i++){
    $a2count=array_sum($a2);

    if($a2count>25){
        $i=$i+1;
        $a2[$i]=$a1[$i];
    }
    else{
        $a2[$i]=$a1[$i];
    }
}

print_r($a2);

I don't know what logic to implement and get result I'm looking for.

Here you go: The logic is not so hard. Hope it helps.

   <?php 

   $a1=array(10,10,10,10,10,10,10,10,10,10);

   $a2 = [];
   $a3 = [];

   $m = 0;

   for($i = 0; $i < count($a1); ++$i){      

        $m += $a1[$i];

        if($m > 25){

           $n = $m % 25;

           if(array_sum($a2) != 25){

               $a2[] = $n;

           }


           $a3[] = implode(',', $a2);       

           $a2 = []; 

           $m = $n;

           $a2[] = $n;


         } else{

           $a2[] = $a1[$i];

         }


   }

   $a3[] = implode(',', $a2);

   print_r($a3);

   ?>

Let me help you a bit using Pseudocode:

ar1 = {10,10,10,20,40,[0]=>1,[0]=>3,[0]=>4};

ar2 = new array (ar.length) \\ worst case

int c = 0; \\current

foreach (ar1 as $value){

ar2 [c]+=ar1[i];

if (ar2 [c]>25){ c++;}

}

Logic behind the code:

Add the value of ar1[i] to the current ar2 value till it passes your limit (25 in this case). If it exceeds you boundary, than move to the next value in the goal array. The worst case would be, that every value is over 25, so it would be an exact copy of the original array.


Here the php code:

$ar1=array(10,10,10,10,10,10,10,10,10,10);

$ar2 = array(0,0,0,0,0,0,0,0,0,0);

$c = 0;

foreach( $ar1 as $key => $value ){

    $ar2[$c]=$value+$ar2[$c];

    if ($ar2[$c]>25){$c++;}

}

Mayhaps something like this will work for you. I will notate so it's not just a copy-and-paste answer. Maybe someone will get some insight on it to improve it in the future:

function slitArray($a1,$num = 25)
    {
        # Used to store the difference when the value exceeds the max
        $store  =   0;
        # Storage container that will be built using sums/diffs
        $new    =   array();
        # Loop through the main array
        foreach($a1 as $value) {
            # If the last key/value pair in our return array is an array
            if(is_array(end($new)))
                # Add up the values in that array
                $sum    =   array_sum(current($new));
            else
                # If not array, no values have been stored yet
                $sum    =   0;
            # This just gets the last key
            $count      =   (count($new)-1);
            # Assign last key
            $i          =   ($count <= 0)? 0 : $count;
            # If the sum of the current storage array plus the value
            # of the current array is greater than our max value
            if(($sum + $value) > $num) {
                # Take max and remove the current total of storage array
                $use            =   ($num-$sum);
                # Take what's left and remove it from the current value
                $store          =   ($value-$use);
                # If the current stored value (the value we want to push to
                # the next storage k/v pair) is more than the max allowed
                if($store > $num) {
                    # Takes a value, checks if it's greater than max,
                    # and if it is, breaks the value up by max as a divider
                    $divide =   function($store,$num)
                        {
                            if($store > $num) {
                                $count  =   ceil($store/$num);
                                for($i=0; $i<$count; $i++) {
                                    $new[]  =   ($store > $num)? $num : $store;
                                    $store  -=  $num;
                                }

                                return $new;
                            }
                            else
                                return array($store);
                        };
                    # This should either be an array with 1 or more values
                    $forward    =   $divide($store,$num);
                    # Do a look forward and add this excess array into our
                    # current storage array
                    $a          =   $i; 
                    foreach($forward as $aVal) {
                        $new[$a+=1][]   =   $aVal;
                    }
                }
                # If the store value is less than our max value, just add
                # it to the next key in this storage array
                else {
                    $new[$i+1][]    =   $store;
                    # Reset the storage back to 0, just incase
                    $store          =   0;
                }
            }
            # Set the current "use" value as the current value in our
            # from-array. Since it doesn't exceed the max, it just gets
            # added to the storage array
            else
                $use    =   $value;
            # Sometimes the math makes $use 0, keep that out of the
            # storage array. The $use value is the current value to add at
            # the time of iteration. Previous storage values are added as
            # future-keys
            if($use > 0)
                $new[$i][]      =   $use;
        }
        # Return the final assembled array
        return $new;
    }

# To use, add array into function
$a1 =   array(10,10,10,10,10,10,10,10,10,10);
# to split using different max value, just add it to second arg
# example: slitArray($a1,20);
print_r(slitArray($a1));

Gives you:

Array
(
    [0] => Array
        (
            [0] => 10
            [1] => 10
            [2] => 5
        )

    [1] => Array
        (
            [0] => 5
            [1] => 10
            [2] => 10
        )

    [2] => Array
        (
            [0] => 10
            [1] => 10
            [2] => 5
        )

    [3] => Array
        (
            [0] => 5
            [1] => 10
            [2] => 10
        )
)

An array input of:

$a1 =   array(23,2,71,23,50,2,3,4,1,2,50,75);

Gives you:

Array
(
    [0] => Array
        (
            [0] => 23
            [1] => 2
        )

    [1] => Array
        (
            [0] => 25
        )

    [2] => Array
        (
            [0] => 25
        )

    [3] => Array
        (
            [0] => 21
            [1] => 4
        )

    [4] => Array
        (
            [0] => 19
            [1] => 6
        )

    [5] => Array
        (
            [0] => 25
        )

    [6] => Array
        (
            [0] => 19
            [1] => 2
            [2] => 3
            [3] => 1
        )

    [7] => Array
        (
            [0] => 3
            [1] => 1
            [2] => 2
            [3] => 19
        )

    [8] => Array
        (
            [0] => 25
        )

    [9] => Array
        (
            [0] => 6
            [1] => 19
        )

    [10] => Array
        (
            [0] => 25
        )

    [11] => Array
        (
            [0] => 25
        )

    [12] => Array
        (
            [0] => 6
        )

)

The final code for this question

<?php 
function slitArray($a1,$num = 25)
{
  $store  =   0;
  $new    =   array();

  foreach($a1 as $value) {

    if(is_array(end($new)))
      $sum    =   array_sum(current($new));
    else
      $sum    =   0;

    $count      =   (count($new)-1);
    $i          =   ($count <= 0)? 0 : $count;

    if(($sum + $value) > $num) {
      $use            =   ($num-$sum);
      $store          =   ($value-$use);
      if($store > $num) {
    $divide =   function($store,$num)
      {
        if($store > $num) {
          $count  =   ceil($store/$num);
          for($i=0; $i<$count; $i++) {
        $new[]  =   ($store > $num)? $num : $store;
        $store  -=  $num;
          }

          return $new;
        }
        else
          return array($store);
      };

    $forward    =   $divide($store,$num);
    $a          =   $i; 
    foreach($forward as $aVal) {
      $new[$a+=1][]   =   $aVal;
    }
      }
      else {
    $new[$i+1][]    =   $store;
    $store          =   0;
      }
    }
    else
      $use    =   $value;

    if($use > 0)
      $new[$i][]      =   $use;
  }

  return $new;
}

$a1 = array(10,20,30,40,50,60);

$arr=slitArray($a1);

print_r($arr);

?>