Binary Search on Answer Technique in DSA Go - 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 does the 'answer' represent?

The 'answer' is the value we want to find, often a number like minimum or maximum that satisfies a problem's condition.

intermediate

Why do we use Binary Search on Answer instead of normal binary search on arrays?

Because sometimes the answer is not directly in a list but lies in a range of values, and we can check if a guess is valid to narrow down the range.

beginner

What is the role of the 'check' function in Binary Search on Answer?

It tests if a guessed answer meets the problem's condition, helping decide if we should search higher or lower.

intermediate

Give a simple example where Binary Search on Answer is useful.

Finding the minimum maximum load to split an array into subarrays with limited sum, by guessing load values and checking feasibility.

What does Binary Search on Answer typically require?

A A range of possible answers and a way to check if a guess is valid

B A sorted array only

C A linked list

D Random guessing

Binary Search on Answer needs a range and a check function to narrow down the answer.

If the check function returns true for a guess, what should you do next?

A Stop immediately

B Search in the upper half

C Search in the lower half to find a better answer

D Ignore and guess randomly

If guess is valid, try to find a smaller valid answer by searching lower.

Binary Search on Answer is best used when:

A The array is unsorted

B You want to find duplicates

C You want to sort an array

D The answer lies in a continuous or discrete range and can be checked

It works when answer is in a range and can be validated by a check.

What is the time complexity of Binary Search on Answer if the check function runs in O(n)?

A O(n log m), where m is the answer range size

B O(n^2)

C O(log n)

D O(n)

Binary search does log m steps, each with O(n) check.

Which of these problems is a good candidate for Binary Search on Answer?

A Reversing a linked list

B Finding minimum maximum subarray sum for splitting

C Finding duplicates in an array

D Sorting an array

Minimum maximum subarray sum can be found by guessing sums and checking feasibility.

Explain the steps to solve a problem using Binary Search on Answer Technique.

Think about guessing and validating answers.

Describe a real-life scenario where Binary Search on Answer can be applied.

Imagine dividing tasks or resources evenly.