Question

How to find the pair in array whose sum is nearest to a number N in a sorted array in PHP

Answer 1

$arr = [3, 5, 7, 12, 18, 20, 23, 27, 30];
 
$size = count($arr);
     
$N = 22;
   
$left = $sum = $nearest_sum = $paira = $pairb = $nearest_sum = 0;
$nearest = PHP_INT_MAX ;
$right = $size - 1;
  
while ($left < $right) {
    $sum = $arr[$left] + $arr[$right];
           
    if (abs($N - $sum) < $nearest) {
        $nearest = abs($N - $sum);
        $nearest_sum = $sum;
        $paira = $arr[$left];
        $pairb = $arr[$right];
    }
           
    if ($sum > $N)
        $right--;
    else if ($sum <= $N)
            $left++;
}
          
echo $nearest_sum . "\n";
echo $paira . " " . $pairb;

 
 
 
/*
run:
   
23
3 20
   
*/

 

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