Binary Search on Answer Technique in DSA Javascript - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the main idea behind the Binary Search on Answer Technique?

It is a method to find an unknown value by guessing an answer range and using binary search to narrow down the correct answer based on a condition check.

beginner

In Binary Search on Answer, what do the 'low' and 'high' variables represent?

'low' and 'high' represent the minimum and maximum possible values of the answer we are searching for.

intermediate

Why do we use a condition function in Binary Search on Answer?

The condition function checks if a guessed answer is valid or not, helping us decide whether to search lower or higher in the answer range.

intermediate

What is a real-life example where Binary Search on Answer can be applied?

Finding the minimum time needed to complete tasks when given a limit on resources, by guessing times and checking feasibility.

intermediate

What is the time complexity of Binary Search on Answer if the answer range is from L to R?

The time complexity is O(log(R - L)) because the search space halves each step.

What does Binary Search on Answer technique help to find?

A The maximum element in an array

B The first element in a sorted array

C The sum of all elements in a list

D An unknown value by searching over a range

Binary Search on Answer guesses an answer in a range and narrows it down using conditions.

Which of these is essential for Binary Search on Answer to work?

A Using recursion only

B Sorting the input array

C A condition to check if a guess is valid

D Having unique elements

The condition function guides the binary search by validating guesses.

If the answer range is from 1 to 1000, how many steps will Binary Search on Answer take at most?

A About 10

B About 100

C About 500

D About 1000

Binary search halves the range each step, so log2(1000) ≈ 10 steps.

What should you do if the condition returns true for a guess in Binary Search on Answer?

A Try searching for a smaller answer

B Try searching for a larger answer

C Stop immediately

D Ignore and guess randomly

If the guess is valid, try smaller values to find the minimum valid answer.

Binary Search on Answer is useful when:

A The input is unsorted

B The answer lies within a known numeric range

C You want to sort an array

D You need to find duplicates

It works by searching over a numeric range where the answer must be.

Explain how Binary Search on Answer technique works step-by-step.

Think about how normal binary search narrows down a search space.

Describe a problem scenario where Binary Search on Answer is a good approach and why.

Consider tasks like minimum time, maximum capacity, or threshold values.