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Understanding Big O Notation in Algorithm Analysis

· 2 min read
Chiluka Akshitha
Chiluka Akshitha
B.Tech (IT) Student

When analyzing algorithms, Big O Notation is a critical concept that helps us understand the performance and efficiency of an algorithm in terms of time and space complexity.

In this blog, we’ll delve into:

  • What is Big O Notation?: An overview of the concept.
  • Common Time Complexities: Exploring the most frequent complexities.

What is Big O Notation?​

Big O Notation describes the upper limit of an algorithm's growth rate, allowing us to express how the runtime or space requirements grow as the size of the input increases.

Common Time Complexities:​

  1. O(1)O(1) - Constant Time
  2. O(n)O(n) - Linear Time
  3. O(logn)O(log n) - Logarithmic Time
  4. O(n2)O(n^2) - Quadratic Time

Example of Time Complexity Analysis​

Consider a simple loop that calculates the sum of an array:

function sumArray(arr) {
  let sum = 0;
  for (let num of arr) {
    sum += num;
  }
  return sum;
}

The time complexity of this function is O(n)O(n), where n is the length of the array.

Space Complexity​

In addition to time complexity, it's essential to consider space complexity, which measures the amount of memory an algorithm uses relative to its input size.

Conclusion​

Understanding Big O Notation is fundamental for analyzing algorithms and making informed decisions when selecting or designing them. By mastering this concept, you will improve your ability to evaluate algorithm performance effectively.