php二分検索
4239 ワード
// function bin_sch($arr,$low,$high,$val)
{
if($low<$high){
$mid = intval(($low+$high)/2);
if($val == $arr[$mid]){
return $mid;
}else if($val < $arr[$mid]){
return bin_sch($arr,$low,$mid-1,$val);
}else{
return bin_sch($arr,$mid+1,$high,$val);
}
}
return -1;
} // function bin_sch($arr,$val)
{
$num = count($arr);
$low = 0;
$high = $c - 1;
while($low <= $high){
$mid = intval(($low + $high)/2);
if($val < $arr[$mid]){
$mid++;
}else if($val > $arr[mid]){
$high--;
}else{
return $mid;
}
}
return -1;
}