PLEASE USE C PROGRAMMING LANGUAGE

PART A. Recursion and complexity calculations 1. Please consider the following function and determine the Big-O notation using recurrence relation. (10 pts.) int fun (int n) { if (n == 0|| n == 1) return n; if (n%3 != 0) return 0; return fun (n/3); } 2. Write a function to find the largest element of an array using ; (20pts.) a. Tail recursion b. Non-tail recursion