Specialist Programmer

Oggy and Cockroaches are playing a game. 'N' cockroaches are hidden inside the holes in a straight line numbered from 1, 2,.., 'N'(i.e. 'i'th cockroach is present at coordinate 'i' where 0 < 'i' <= 'N'). At the time 't', the cockroach at position 'X[t]' comes out of the hole with 'A[t]' coins where 0 < 't' <= 'N'. Initially, at time 't' = 0, Oggy is at coordinate 0 and has 0 coins. Each second, he can remain idle or move only to its adjacent coordinates.

Oggy can collect the coins from 'i'th cockroach only if he is at the coordinate 'i' exactly when it appears.

You can assume that no time is taken to collect the coins.

Return a number 'C' denoting the maximum number of coins Oggy can collect.

Note: Assume 1-based indexing.

For example:

Let 'N' = 5, 'X' = [1, 2, 4, 3, 5] and 'A' = [20, 0, 10, 0, 1]. 
Oggy moves to position 1 and collects 'A[1]' coins at time t = 1. Then, Oggy will move to position 5, which takes 4 seconds. So, at time t = 5, he will collect 1 coin. In total, he will be able to collect 21 coins. 
Hence, the answer will be 21.

Ninja got a map in his hand with ‘N’ cities numbered 0 to ‘N’, connected with bridges. He asks his sister to delete some cities from the map.

He will ask his sister a ‘Q’ query. Each query is denoted by an integer ‘X’, meaning that he will delete the city ‘X’. He wants to see if the new map obtained after deleting the city node will have more connected components than the previous map.

He wants to build the program for the queries given by his sister for the above condition.

Ninja knows that you are a very good programmer and can help him in writing the code for the above. Help Ninja!

Note:

A connected component in the map is the maximum subset of cities that are connected i.e we can go from one city to any other in that subset.

Sort the given biotonic doubly linked list.

Note :

Biotonic Doubly linked list is the one which is first increasing and then decreasing. A strictly increasing or strictly decreasing doubly linked list is also biotonic.

You have been given an array/list ‘EDGES’ of size (N - 1) x 2 representing the undirected connected tree with ‘N’ nodes from 0…’N’ - 1 and ‘N’ - 1 edges such that the i’th edge connects ‘EDGES[i][0]’ node with ‘EDGES[i][1]’ node.

You need to print an array/list ‘ANS’, where ANS[i] is the sum of the distances between node ‘i’ and all other nodes.

For example:

For ‘N’ = 6 and ‘EDGES’ = [ [0,1], [0, 2], [2, 3], [2, 4], [2, 5] ], see the below picture for reference:

1. For node 0:
   a. Distance from node 0 to node 1 is 1.
   b. Distance from node 0 to node 2 is 1.
   c. Distance from node 0 to node 3 is 2.
   d. Distance from node 0 to node 4 is 2.
   e. Distance from node 0 to node 5 is 2.
   So the sum of all the distances is 8.

2. For node 1:
   a. Distance from node 1 to node 0 is 1.
   b. Distance from node 1 to node 2 is 2.
   c. Distance from node 1 to node 3 is 3.
   d. Distance from node 1 to node 4 is 3.
   e. Distance from node 1 to node 5 is 3.
   So the sum of all the distances is 12.

3. For node 2:
   a. Distance from node 2 to node 0 is 1.
   b. Distance from node 2 to node 1 is 2.
   c. Distance from node 2 to node 3 is 1.
   d. Distance from node 2 to node 4 is 1.
   e. Distance from node 2 to node 5 is 1.
   So the sum of all the distances is 6.

4. For node 3:
   a. Distance from node 3 to node 0 is 2.
   b. Distance from node 3 to node 1 is 3.
   c. Distance from node 3 to node 2 is 1.
   d. Distance from node 3 to node 4 is 2.
   e. Distance from node 3 to node 5 is 2.
   So the sum of all the distances is 6.

5. For node 4:
   a. Distance from node 4 to node 0 is 2.
   b. Distance from node 4 to node 1 is 3.
   c. Distance from node 4 to node 2 is 1.
   d. Distance from node 4 to node 3 is 2.
   e. Distance from node 4 to node 5 is 2.
   So the sum of all the distances is 6.

6. For node 5:
   a. Distance from node 5 to node 0 is 2.
   b. Distance from node 5 to node 1 is 3.
   c. Distance from node 5 to node 2 is 1.
   d. Distance from node 5 to node 3 is 2.
   e. Distance from node 5 to node 4 is 2.
   So the sum of all the distances is 6.

So, ‘ANS’ for the above example will be [8, 12, 6, 10, 10, 10].

You are given an arbitrary binary tree consisting of 'N' nodes numbered from 1 to 'N'. Your task is to print all the root to leaf paths of the binary tree.

A leaf of a binary tree is the node which does not have a left child and a right child.

For Example :

Given a binary tree :

All the root to leaf paths are :
1 2 4
1 2 5 
1 3

Note :

1. Two nodes may have the same value associated with it.
2. The root node will be fixed and will be provided in the function.
3. Note that the nodes in a path will appear in a fixed order. For example, 1 2 3 is not the same as 2 1 3.
4. Each path should be returned as a string consisting of nodes in order and separated by a space.
5. The path length may be as small as ‘1’.

Design a scalable system similar to a flight booking platform like MakeMyTrip, where users can:

• Search for flights between two cities
• View available flights with prices and timings
• Book tickets
• Make payments
• View booking history

• What is lock granularity?
• What is intention locking?

Find all users who have logged in for at least three consecutive days.

SELECT user_id
FROM (
    SELECT 
        user_id,
        login_date,
        DATE_SUB(login_date, INTERVAL ROW_NUMBER() OVER (PARTITION BY user_id ORDER BY login_date) DAY) AS grp
    FROM logins
) t
GROUP BY user_id, grp
HAVING COUNT(*) >= 3;

Given a table logins:

| user_id | login_date |

Find the longest consecutive login streak for each user.