Summation Triangle sucessful submission in C

[vcnovaes]

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Description

This is a solution for the problem summation triangle of the Code Wars site: Summation Triangle - Code Wars

Above you have the problem description!

In this code we have two solutions but only the pg_approach(unsigneed n) is accepted by CodeWars, the brute_force(int n) approach fails in terms of complexity, so it's not accepted by CodeWars, but it gives the right results :heart: Thank you!