# DST Unit 1 – Introduction to Data Structure

On this page, you will find all the most important and most asked questions from unit 1 of the data structure subject.

### Key Note:

• Data Structure is a way to organize data so that we can perform any operation on it efficiently.
• Data type describes which type of value a variable can store. Means if a variable is of int data type it means that, that particular variable can store only integer data.
• Built-in data type is also known as predefined data type which can be directly used by any programmer to a variable types and assign value in it.
• Some example of built-in data type are int, char, float, double, short, long etc.

### Key Note:

• Algorithm can be defined as a step by step approach  to solve a problem in finite steps and time. It is a human-readable solution.
• Efficiency of an Algorithm shows the quality of algorithm. Here the parameter for quality is algorithm should take less time and space to solve any problem.
• Time complexity shows time taken by an algorithm to solve a problem.
• Space complexity show space/memory taken by an algorithm to solve a problem.

### Key Note:

• Asymptotic notation helps to measure the complexity of an algorithm. It is of 5 types Big-Oh, Omega, Theta, Little Oh and Little Omega.
• An Abstract datatype is a datatype, whose behavior is defined by a set of values and set of operations. for example stack and queue is a perfect example of ADT.