I didn't understand how the output will come 240 can you clear my doubt ❓

Question

Title: The coding Challenges
Problem: There are n participants appearing for one on one coding challenge.Each participant plays twice (challenges) with each of his opponents.You need to compute the total number of challenges.
Input: First line contains an integer n, represent number of participants.
Output: Print the total number of challenges.
Constraints: 1≤n≤100
Sample Input: 16
Sample Output:
240

Answer 1

Let's look at a smaller example.
Sample Input: 3
Sample Output: 6

There are 3 participants, A, B, C. Each one of them plays twice against each of their opponnents. The matches are:

A - B
A - B
A - C
A - C
B - C
B - C

Can you work it out for n=16?

Answer 2

in python you can do it with 2 nested for loops to generate tuples like this:

(1,2), (1,3),...

keep in mind that equal pairs are not valid e.g. (1,1),...
so finally you get 240 pairs.

a general calculation for the number of pairs is: (n1 + n2 + ... + n15) *2. so result of summation is 120 * 2 = 240.

Answer 3

Thaks you #mr Diego

I understood 😃