PHP递归与非递归实现二分查找

// 递归二分查找
$arr = [1,2,3,4,11,12,124,1245];
function bin_recur_find($arr, $beg, $end, $v) {
if ($beg <= $end) {
$idx = floor(($beg + $end)/2);
if ($v == $arr[$idx]) {
return $idx;
} else {
if ($v < $arr[$idx]) {
return bin_recur_find($arr, $beg, $idx - 1, $v);
} else {
return bin_recur_find($arr, $idx + 1, $end, $v);
}
}
}
return -1;
}
// 非递归二分查找
function bin_find($arr, $v) {
$beg = 0;
$end = count($arr) - 1;
while ($beg <= $end) {
$idx = floor(($beg + $end)/2);
if ($v == $arr[$idx]) {
return $idx;
} else {
if ($v < $arr[$idx]) {
$end = $idx - 1;
} else {
$beg = $idx + 1;
}
}
}
return -1;
}

echo bin_recur_find($arr, 0, count($arr) - 1, 100) . "\n";
echo bin_find($arr, 100) . "\n";