Allocate Minimum Pages Binary Search on Answer in DSA C++ - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the main goal of the Allocate Minimum Pages problem?

To divide an array of book pages among students such that the maximum pages assigned to a student is minimized.

intermediate

Why do we use binary search in the Allocate Minimum Pages problem?

Because the answer (minimum maximum pages) lies between the maximum single book pages and the sum of all pages, allowing us to search efficiently in this range.

intermediate

What does the 'isPossible' function check in this problem?

It checks if it is possible to allocate books to students such that no student reads more than a given maximum number of pages.

beginner

What is the initial search range for binary search in this problem?

The lower bound is the maximum pages in a single book, and the upper bound is the sum of all pages in all books.

intermediate

How does the binary search update its range during the solution?

If allocation is possible with mid as max pages, it tries to find a smaller max by moving upper bound to mid; otherwise, it moves lower bound to mid + 1.

What is the lower bound for binary search in Allocate Minimum Pages?

A Maximum pages in a single book

B Sum of all pages

C Zero

D Number of students

The minimum maximum pages cannot be less than the largest single book.

What does the 'isPossible' function return if allocation is not feasible?

A True

B Number of students

C False

D Sum of pages

'isPossible' returns false if allocation with given max pages is not possible.

If allocation is possible with mid pages, what should binary search do next?

A Increase upper bound

B Increase lower bound

C Stop searching

D Decrease upper bound

Try to find a smaller maximum by decreasing upper bound.

What is the time complexity of the binary search approach for this problem?

A O(n log(sum of pages))

B O(n^2)

C O(log n)

D O(n)

Binary search over the range of sum of pages with O(n) feasibility check.

What does the final answer represent in Allocate Minimum Pages?

A Number of students

B Maximum pages assigned to any student

C Total pages of all books

D Minimum pages assigned to any student

It is the minimized maximum pages assigned to any student.

Explain how binary search is applied to solve the Allocate Minimum Pages problem.

Think about how to guess the answer and check if it works.

Describe the role of the 'isPossible' function in the Allocate Minimum Pages problem.

It tests if a guess is valid.