Question

How to find the floor of N in a sorted array with PHP

Answer 1

// floor of N = the largest element in the array smaller than or equal to N

function find_the_floor($arr, $N) {
    $size = count($arr);
    
    if ($N >= $arr[$size - 1]) {
        return $size - 1;
    }
    
    if ($N < $arr[0]) {
        return -1;
    }
    
    for ($i = 1; $i < $size; $i++) {
        if ($arr[$i] > $N) {
            return $i - 1;
        }
    }
    return -1;
}

$arr = array(1, 2, 7, 8, 14, 19, 20, 24, 28);
$N = 17;

$index = find_the_floor($arr, $N);

if ($index == -1) {
    echo "The floor doesn\'t exist in array";
}
else {
    echo "The floor of " . $N . " is " . $arr[$index];
}


 
/*
run:
    
The floor of 17 is 14
        
*/

 

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