# Algorithms | Analysis of Algorithms | Question 2

What is the time complexity of fun()?

`int` `fun(` `int` `n)` `{` ` ` `int` `count = 0;` ` ` `for` `(` `int` `i = 0; i < n; i++)` ` ` `for` `(` `int` `j = i; j > 0; j--)` ` ` `count = count + 1;` ` ` `return` `count;` `} ` |

**(A)** Theta (n)**(B)** Theta (n^2)**(C)** Theta (n*Logn)**(D)** Theta (nLognLogn)**Answer:** **(B)****Explanation:** The time complexity can be calculated by counting number of times the expression “count = count + 1;” is executed. The expression is executed 0 + 1 + 2 + 3 + 4 + …. + (n-1) times.

Time complexity = Theta(0 + 1 + 2 + 3 + .. + n-1) = Theta (n*(n-1)/2) = Theta(n^{2})

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