php实现二分查找算法
// $low and $high have to be integers function BinarySearch( $array, $key, $low, $high ) { if( $low > $high ) // termination case { return -1; } $middle = intval( ( $low+$high )/2 ); // gets the middle of the array if ( $array[$middle] == $key ) // if the middle is our key { return $middle; } elseif ( $key < $array[$middle] ) // our key might be in the left sub-array { return BinarySearch( $array, $key, $low, $middle-1 ); } return BinarySearch( $array, $key, $middle+1, $high ); // our key might be in the right sub-array }