Compute Big o

Find the runtime of the code shown below:

int qux(int n) { int a = 0; for (int i = n; i > 0; i--) { for (int j = 0; j < i; j++) { a = a + i + j; } } return a; } 

Input Format

N, the input to the function, for example:

10

Constraints

None

Output Format

One of the following

• O(log n)
• O(n)
• O(n log n)
• O(n^2)
• O(n^3)
• O(2^n)
• O(n^n)

Sample Input 0

10 

Sample Output 0

O(log n) 

Given code for answer:

import java.io.*; import java.util.*;

public class Solution {

public static void main(String[] args) { /* Enter your code here. Read input from STDIN. Print output to STDOUT. Your class should be named Solution. */ } }