所以我现在要做一个猜测（这听起来像是在做作业时作弊）。
您需要输出两个名称之和为500的名称对（输入）。
这可能不是最优的解决方案，但它应该是一个有效的解决方案？

$input = 500;

// using shorthand array formatting

$array1 = [
    200 => 'jhon',
    300 => 'puppy',
    50 => 'liza',
    150 => 'rehana',
    400 => 'samra',
    100 => 'bolda'
];

// create an array that holds names we have already processed.
$namesProcessed = [];

// loop over the names trying to find a compatible partner

foreach ($array1 as $points => $name) {
    
    foreach ($array1 as $pointsPotentialPartner => $namePotentialPartner) {

        // Don't partner with yourself...
        if ($name == $namePotentialPartner) {
            continue;
        }

        // Don't partner with someone that has already been processed.
        if (in_array($namePotentialPartner, $namesProcessed)) {
            continue;
        }

        // test if the two partners add up to the input
        if ($input == ($points + $pointsPotentialPartner)) {

           // if this is the first partner set, don't put in 'and'

           if (count($namesProcessed) == 0) {
               echo $name . ', ' . $namePotentialPartner;
           } else {
               echo ' and ' . $name . ', ' . $namePotentialPartner;
           }

           $namesProcessed[] = $name;
           $namesProcessed[] = $namePotentialPartner;
        }
    }
}

希望这个有用。