Tip 1 : Practice Atleast 250 Questions
Tip 2 : Ex- Do atleast 2 projects
Tip 1 : Have some projects on resume.
Tip 2 : Do not put false things on resume.
3 coding questions



Given a matrix of dimension m*n where each cell in the matrix can have values 0, 1 or 2 which has the following meaning:
0: Empty cell
1: Cells have fresh oranges
2: Cells have rotten oranges
Determine what is the minimum time required so that all the oranges become rotten. A rotten orange at index [i,j] can rot other fresh orange at indexes [i-1,j], [i+1,j], [i,j-1], [i,j+1] (up, down, left and right). If it is impossible to rot every orange then simply return -1.
Approach: The idea is to use Breadth First Search. The condition of oranges getting rotten is when they come in contact with other rotten oranges. This is similar to breadth-first search where the graph is divided into layers or circles and the search is done from lower or closer layers to deeper or higher layers. In the previous approach, the idea was based on BFS but the implementation was poor and inefficient. To find the elements whose values are no the whole matrix had to be traversed. So that time can be reduced by using this efficient approach of BFS.



1. A node will be in the bottom-view if it is the bottom-most node at its horizontal distance from the root.
2. The horizontal distance of the root from itself is 0. The horizontal distance of the right child of the root node is 1 and the horizontal distance of the left child of the root node is -1.
3. The horizontal distance of node 'n' from root = horizontal distance of its parent from root + 1, if node 'n' is the right child of its parent.
4. The horizontal distance of node 'n' from root = horizontal distance of its parent from the root - 1, if node 'n' is the left child of its parent.
5. If more than one node is at the same horizontal distance and is the bottom-most node for that horizontal distance, including the one which is more towards the right.
Input: Consider the given Binary Tree:

Output: 4 2 6 3 7
Explanation:
Below is the bottom view of the binary tree.

1 is the root node, so its horizontal distance = 0.
Since 2 lies to the left of 0, its horizontal distance = 0-1= -1
3 lies to the right of 0, its horizontal distance = 0+1 = 1
Similarly, horizontal distance of 4 = Horizontal distance of 2 - 1= -1-1=-2
Horizontal distance of 5 = Horizontal distance of 2 + 1= -1+1 = 0
Horizontal distance of 6 = 1-1 =0
Horizontal distance of 7 = 1+1 = 2
The bottom-most node at a horizontal distance of -2 is 4.
The bottom-most node at a horizontal distance of -1 is 2.
The bottom-most node at a horizontal distance of 0 is 5 and 6. However, 6 is more towards the right, so 6 is included.
The bottom-most node at a horizontal distance of 1 is 3.
The bottom-most node at a horizontal distance of 2 is 7.
Hence, the bottom view would be 4 2 6 3 7
The following are steps to print Bottom View of Binary Tree.
1. We put tree nodes in a queue for the level order traversal.
2. Start with the horizontal distance(hd) 0 of the root node, keep on adding left child to queue along with the horizontal distance as hd-1 and right child as hd+1.
3. Also, use a TreeMap which stores key value pair sorted on key.
4. Every time, we encounter a new horizontal distance or an existing horizontal distance put the node data for the horizontal distance as key. For the first time it will add to the map, next time it will replace the value. This will make sure that the bottom most element for that horizontal distance is present in the map and if you see the tree from beneath that you will see that element.



The problem can be easily solved by applying DFS() on each component. In each DFS() call, a component or a sub-graph is visited. We will call DFS on the next un-visited component. The number of calls to DFS() gives the number of connected components. BFS can also be used.
Coding questions along with some DBMS and OS concepts .



a) push(int x) : 'x' has to be inserted in the priority queue. This has been implemented already
b) pop() : return the maximum element in the priority queue, if priority queue is empty then return '-1'.
We perform the following operations on an empty priority queue:
When operation push(5) is performed, we insert 1 in the priority queue.
When operation push(2) is performed, we insert 2 in the priority queue.
When operation pop() is performed, we remove the maximum element from the priority queue and print which is 5.
When operation push(3) is performed, we insert 1 in the priority queue.
When operation pop() is performed, we remove the maximum element from the priority queue and print which is 3.



If two rows have the same number of 1’s, return the row with a lower index.
If no row exists where at-least one '1' is present, return -1.
Input: ‘N’ = 3, 'M' = 3
'ARR' =
[ [ 1, 1, 1 ],
[ 0, 0, 1 ],
[ 0, 0, 0 ] ]
Output: 0
Explanation: The 0th row of the given matrix has the maximum number of ones.
Since each row is sorted, we can use Binary Search to count of 1s in each row. We find the index of first instance of 1 in each row. The count of 1s will be equal to total number of columns minus the index of first 1.
What is meant by ACID properties in DBMS?
What you mean by normalisation and it's types?
Which is your dream company other than Oyo?
Why do you want to join Oyo?
Tell me about your projects.

Here's your problem of the day
Solving this problem will increase your chance to get selected in this company
How do you remove whitespace from the start of a string?