Range Queries and Copies

Your task is to maintain a list of arrays which initially has a single array. You have to process the following types of queries: - Set the value a in array k to x. - Calculate the sum of values in range [a,b] in array k. - Create a copy of array k and add it to the end of the list. Input The first input line has two integers n and q: the array size and the number of queries. The next line h