php实现二分查找算法

1. // $low and $high have to be integers
3. function BinarySearch( $array, $key, $low, $high )
4. {
5. if( $low > $high ) // termination case
6. {
7. return -1;
8. }
10. $middle = intval( ( $low+$high )/2 ); // gets the middle of the array
12. if ( $array[$middle] == $key ) // if the middle is our key
13. {
14. return $middle;
15. }
16. elseif ( $key < $array[$middle] ) // our key might be in the left sub-array
17. {
18. return BinarySearch( $array, $key, $low, $middle-1 );

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