Analyze The Run Time Of This Function In Terms Of Asymptotic Order Please Explai

Analyze the run time of this function in terms of asymptotic order;

PLease explain

{  i , j;   sum; arr = [n];   (i= ; i <n; i+= )    arr[i] = (i+);sum =;   (i =; i<n; i ++)     (j =; j <= arr[i]; j++)      sum += (i+j); []arr; sum;