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# D1 binary search help watch

1. Hi, I am uncertain about how part b is worked out. From part a, I know that 3 comparisons are needed to find Hussein. So does it mean that the maximum no of comparison in any list would be the actual number of comparisons +1? If not, how is 4 deduced for b?

Thanks
2. (Original post by coconut64)
Hi, I am uncertain about how part b is worked out. From part a, I know that 3 comparisons are needed to find Hussein. So does it mean that the maximum no of comparison in any list would be the actual number of comparisons +1? If not, how is 4 deduced for b?

Thanks
The maximum number of comparisons in a binary search where there are n items is

Because the list essentially divides by 2 each time.
3. (Original post by NotNotBatman)
The maximum number of comparisons in a binary search where there are n items is

Because the list essentially divides by 2 each time.
Does this work for all binary search questions? Cheers
4. (Original post by coconut64)
Does this work for all binary search questions? Cheers
For maximum number of comparisons only, yes.

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