Given an integer N and an array containing N elements. Also given an integer Q denoting the number of queries. Query consist of three integers, T, X and Y. T denotes the query type and can take values 0 and 1. X denotes the starting position of the query. Y denotes the increment in position. Type 0 is for addition and Type 1 is for multiplication. For eg: Given N = 5,

arr[] = 1 2 3 4 5

Q=2,

0 2 2

1 1 3

For first query, T=0, X=2, Y=2. So we have to return sum of arr[X] + arr[X+Y] + arr[X+2Y] till end of array. Here it would be arr[2] + arr[4] = 3+5=8

For second query, T=1, X=1, Y=3. So we have to return product of arr[X] * arr[X+Y] * arr[X+2Y] till end of array. Here, arr[1] * arr[4] = 2 * 5 =10

As the answer can be large, return ans modulo 10^9+7.

N,Q <= 10^5

arr[i] <= 10^9

https://cses.fi/problemset/task/1704 Please give any hints to this problem. I have been stuck for quiet a while.

Syrjälä's network consists of n computers and n−1 connections between them. It is possible to send data between any two computers.

However, if any connection breaks down, it will no longer be possible to send data between some computers. Your task is to add the minimum number of new connections in such a way that you can still send data between any two computers even if any single connection breaks down.

Can anyone suggest resources or question to practice and learn combinatoorial problems.