Two-part method PHP

To start learning some algorithms recently ... Some algorithms will make you sigh true to the clever. I think some algorithms have been invented and need to be a mathematician. Such as quick sort, simply sigh how he thought of ... No other people's intelligence can only read more than remember haha ~

Today write a simple algorithm, dichotomy.

<?PHPfunctionBsearch ($v,$arr){    $low= 0; $high=Count($arr)-1;//use subscript, note minus 1     while($low<=$high){//Note the equals sign        $i=intval(($high+$low)/2); if($arr[$i] >$v){            $high=$i-1; } Else if($arr[$i] <$v){            $low=$i+1; } Else {            return  $i; }    }    return-1;//returned when not found-1}$arr=Array(    1, 3, 5, 7, 9, 13);EchoBsearch (13,$arr);//5Echo' ;EchoBsearch (14,$arr);//-1

Seemingly simple algorithm, or self-write down good haha ~

Note that when using the while, be sure to guard against infinite loops, pay attention to the termination of the cycle of judgment. For example $low<= $high, this equals number must have.

Two-part method PHP