SDE - 1

You are given an unweighted directed graph having 'V' vertices and 'E' edges. Your task is to count the number of strongly connected components (SCCs) present in the graph.

A directed graph is said to be strongly connected if every vertex is reachable from every other vertex. The strongly connected components of a graph are the subgraphs which are themselves strongly connected.

Note :

Use zero-based indexing for the vertices.

The given graph doesn’t contain any self-loops.

The gardener wants to water the garden by opening the minimum number of taps. The garden is one-dimensional along the x-axis of length N i.e. the garden starts from point 0 and ends at point N. There are N + 1 tap located at points [0, 1, 2, …, N] in the garden.

You are given an integer N, and an array named “ranges” of size N + 1(0-indexed). The ith tap, if opened, can water the gardener from point (i - ranges[i]) to (i + ranges[i]) including both. The task is to find the minimum number of taps that should be open to water the whole garden, return -1 if the garden can not be watered.

Example :

Follow Up:

Can you solve the problem in O(N) time?

You are given an arbitrary binary tree, a node of the tree, and an integer 'K'. You need to find all such nodes which have a distance K from the given node and return the list of these nodes.

Distance between two nodes in a binary tree is defined as the number of connections/edges in the path between the two nodes.

Note:

1. A binary tree is a tree in which each node has at most two children. 
2. The given tree will be non-empty.
3. The given tree can have multiple nodes with the same value.
4. If there are no nodes in the tree which are at distance = K from the given node, return an empty list.
5. You can return the list of values of valid nodes in any order. For example if the valid nodes have values 1,2,3, then you can return {1,2,3} or {3,1,2} etc.

Example :

Consider this tree above. The target node is 5 and K = 3. The nodes at distance 1 from node 5 are {2}, nodes at distance 2 from node 5 are {1, 4} and nodes at distance 3 from node 5 are {6, 3}.

Ninja has created his own encryption technique to encrypt a number. He makes use of the logic behind factorial. In a factorial, we multiply the number by its previous number and so on but if we want to encrypt a number we don’t multiply in every step like in the case of factorial but multiply, divide, add and subtract and repeat in the same order.

So your task is to find the encrypted form of a number using the ninja encryption technique and you were being provided with the number.