What does the following code do$?$ Give a big$-$Oh characterization, in terms of $n,$ of the running time.

public static int example $($int$[]$ arr$)\{$

int $n=$ arr.length, total $=0$;

for $($ int $+=$ars$[]=1+2+3+9+$dots$+n-1=\frac{(n-1)n}{2}O(n^2)=\{-2,3,1,6,5\}+18k=0$;$kj=0$;$j$