SDE - 1

You are given a string 'str' of lowercase alphabets and an integer 'k' .

Your task is to return the count all the possible substrings that have exactly 'k' distinct characters.

For example:

'str' = abcad and 'k' = 2. 

We can see that the substrings {ab, bc, ca, ad} are the only substrings with 2 distinct characters. 

Therefore, the answer will be 4.    

Ninja Land can be represented as a N * N grid in the XY plane. Each cell of this grid can have a building of some height.

You are given a matrix ‘GRID[][]’ of size ‘N’ * ‘N’, where ‘GRID[i][j]’ gives the height of the building at cell (i, j) in XY plane. Note, building at any cell (i, j) is represented as a cuboid that is an axis aligned with the axis ‘X’, ‘Y’, ‘Z’ and has the dimension 1 * 1 * GRID[i][j] along X, Y, Z-axis respectively.

Ninja views the projection of these buildings onto the XY, YZ, and ZX planes. A projection is like a shadow, that maps a 3-dimensional figure to a 2-dimensional plane. We are viewing the "shadow" when looking from the top, the side, and the front, in XY, YZ, ZX plane respectively.

Your task is to find and return the total area of all three projections. See the example for more clarity.

Note:

 ‘GRID[i][j]’ = 0, if there is no building at cell (i, j).

Example:

Consider the following 2*2 ‘GRID[][]’:
                [1, 2]
                [3, 4]

Its projection in XY, YZ, XZ plane is shown below -: 

Area covered in XY plane is 4, Area covered in YZ plane is 6, Area covered in ZX plane is 7, Thus the total area is 4 + 6 + 7 = 17.

Ninja is given the task to create a perfect gift for the king. He has ‘N’ wraps to choose from which he can choose to wrap the gifts. He also has ‘M’ gifts from which he can choose the gifts for the king. To choose the gifts, he sets some rules:

1) He must select exactly one wrapper to wrap all the chosen gifts.
2) He can select one or more gifts or no gifts at all.
3) He has 2 copies of the same gift. So, he can take 0 or 1 or 2 copies of each gift.

He also has a number ‘X’. He decided to spend in such a way that the total cost is as close as ‘X’. If there are multiple answers, print the minimum one.

For example:

Let’s say you have two wrappers with cost [1, 2] and three gifts with cost [3, 4, 5] and ‘X’ = 7. In the first case, you select wrapper number ‘2’ and gift number ‘1’ and ‘3’, so your total cost will be 2 + 3 + 5 = 10. While in the second case, you select wrapper number ‘1’ and gift number ‘2’, so your total cost will be 1 + 4 = 5. So out of both the cases, second case is closer to ‘X’ as abs(7 - 5) = 2 and abs(7 - 10) = 3.

You are given a directed and unweighted graph of 'V' vertices and 'E' edges. All edges are given in a 2-dimensional array of ‘Edges’ in which ‘Edges[i][0]’ and ‘Edges[i][1]’ contain an edge. Your task is to check if there exists a path from the vertex 'source' to 'destination'.

Given an undirected and disconnected graph G(V, E), containing 'V' vertices and 'E' edges, the information about edges is given using 'GRAPH' matrix, where i-th edge is between GRAPH[i][0] and GRAPH[i][1]. print its DFS traversal.

V is the number of vertices present in graph G and vertices are numbered from 0 to V-1. 

E is the number of edges present in graph G.

Note :

The Graph may not be connected i.e there may exist multiple components in a graph.

You are given several boxes with different colours represented by different positive numbers. For moving the boxes you can remove them in multiple iterations until there are no boxes left. Now, every time you can choose some continuous boxes with the same color (i.e., composed of 'k' boxes, 'k' >= 1), remove them and get 'k' * 'k' points for removing them.

Your task for the problem is to find and return the maximum points you can get by removing those boxes.

For Example:

Input: boxes = [1, 3, 2, 2, 2, 3, 4, 3, 1]
Output: 23
Explanation:
[1, 3, 2, 2, 2, 3, 4, 3, 1] 
----> [1, 3, 3, 4, 3, 1] (Remove 3 boxes with number 2, 3*3=9 points) 
----> [1, 3, 3, 3, 1] (Remove one box with number 4, 1*1=1 points) 
----> [1, 1] (Remove 3 boxes with number 3, 3*3=9 points) 
----> [] (2*2=4 points)