Hands-On Data Structures and Algorithms with JavaScript

Linear time

Let's now discuss one of the most common time complexities, the linear time. As one can guess, linear time complexity of a method indicates that the method takes linear time to execute: 

for(var i = 0; i < N; i += c) {    // O(1) operations}

This is a very basic for loop, within which we are performing some constant time operations. As the size of N increases, the number of the times the loop gets executed also increases.

As you can see, the value of i in each iteration is incremented by a constant, c, and not by 1. This is because it does not matter what the increments are, as long as they are linear.

In the first iteration, the value of i = 0; in the second iteration, the value of i = c, then its c + c = 2c in the third iteration, ...