Binary Search

This lecture introduces the binary search algorithm, emphasizing the need for a sorted input array. The instructor explains the binary search process, comparing it to linear search, and demonstrates how to find a target value by iteratively narrowing down the search range using middle elements. The lecture includes examples with pointers and discusses conditions for updating pointers. The session concludes with a brief mention of the algorithm's complexity, hinting at logarithmic behavior, and sets the stage for the next lecture on implementation and complexity analysis.

What is a necessary condition for applying the binary search algorithm?

• The array must have an even number of elements.

• The array must contain only integers.

• The array must be sorted.

• The array must be in descending order.

In binary search, what is the first step after identifying the middle element?

• Check if the array is empty.

• Divide the array into two equal parts.

• Sort the array again.

• Compare the middle element with the target value.

How does binary search utilize the sorted order of an array?

• By rearranging the elements.

• By narrowing the search to one half of the array.

• By jumping to random elements.

• By comparing each element sequentially.

What role do pointers play in the binary search algorithm?

• They store the target value.

• They track the current middle, left, and right positions.

• They are used to count the number of elements.

• They help in sorting the array.

What happens if the middle element is greater than the target in binary search?

• The search continues in the right half.

• The search continues in the left half.

• The search stops immediately.

• The array is sorted again.

When do you update the left pointer in binary search?

• When the middle element is equal to the target.

• When the middle element is greater than the target.

• When the middle element is less than the target.

• When the array is unsorted.

What indicates that the target is not present in the array during binary search?

• The array is sorted again.

• The array is fully traversed.

• The middle element is equal to the target.

• The left and right pointers cross each other.

What should be returned if the target is not found in the array?

• The index of the last element.

• Zero.

• The index of the first element.

• Minus one.

What is the next topic to be discussed after understanding binary search?

• Implementation and complexity analysis.

• Sorting algorithms.

• Data structures.

• Linear search.

What mathematical concept helps in understanding the complexity of binary search?

• Algebra.

• Geometry.

• Calculus.

• Logarithm.