I need help with problem 3. Not number 2. This is a coding program that needs to be done in C++.

2. What is the runtime complexity of the following code fragments in big-O notation as functions of m and/or n? Explain each answer. (Your answers should represent the tightest/closest function for the code given.) a. int sum = 0; for (inti 1; i n it+) for (int j = 1; j n; jt-2) sum += (1+1); b, int sum= for (int = 1; i