Insert Interval into Sorted List in DSA C - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the main goal when inserting an interval into a sorted list of intervals?

To add the new interval into the correct position in the list and merge any overlapping intervals to keep the list sorted and non-overlapping.

beginner

How do you determine if two intervals overlap?

Two intervals overlap if the start of one interval is less than or equal to the end of the other interval, and the start of the other interval is less than or equal to the end of the first interval.

intermediate

Why is it important to keep the list of intervals sorted after insertion?

Keeping the list sorted helps efficiently find where to insert new intervals and makes merging overlapping intervals easier and faster.

intermediate

What is the time complexity of inserting an interval into a sorted list and merging overlaps?

The time complexity is O(n), where n is the number of intervals, because you may need to check and merge intervals across the entire list.

beginner

In C, what data structure is commonly used to represent an interval for this problem?

A struct with two integer fields, usually named start and end, to represent the beginning and end of the interval.

What should you do first when inserting a new interval into a sorted list?

A Merge all intervals first

B Find the correct position to insert the new interval

C Delete overlapping intervals

D Sort the list again

You first find where the new interval fits in the sorted list before merging overlaps.

When do two intervals NOT overlap?

A When one interval is inside the other

B When they share a boundary point

C When one interval ends before the other starts

D When they have the same start

Intervals do not overlap if one ends before the other begins.

What is the result after merging overlapping intervals?

A A list with no overlapping intervals

B A list with all intervals doubled

C A list sorted in descending order

D A list with only the new interval

Merging removes overlaps so the list has only non-overlapping intervals.

Which data structure is best to store intervals for this problem in C?

A String array

B Linked list of integers

C Single integer variable

D Array of structs with start and end fields

An array of structs holding start and end values is ideal for intervals.

What is the main challenge when inserting an interval into a sorted list?

A Merging overlapping intervals correctly

B Finding the maximum interval

C Sorting the list in reverse

D Deleting all intervals

The key challenge is merging any intervals that overlap with the new one.

Explain step-by-step how to insert a new interval into a sorted list of intervals and merge overlaps.

Think about scanning the list from start to end and handling intervals in three parts.

Describe how you check if two intervals overlap and how to merge them.

Overlap means intervals touch or cross; merging combines their ranges.