SDE - 1

You are given a square matrix of non-negative integers 'MATRIX'. Your task is to rotate that array by 90 degrees in an anti-clockwise direction using constant extra space.

For example:

For given 2D array :

    [    [ 1,  2,  3 ],
         [ 4,  5,  6 ],
         [ 7,  8,  9 ]  ]

After 90 degree rotation in anti clockwise direction, it will become:

    [   [ 3,  6,  9 ],
        [ 2,  5,  8 ],
        [ 1,  4,  7 ]   ]

What are semaphores?
What is memory management unit?

Given the count of total stones in a game. Two-player ‘Ale’ and ‘Bob’ are playing the game. Your task is to find who will win the game if both the players are playing optimally.

Rules of the game.

1. In a single turn, a player can choose a single stone or ‘even’ number of stones.

2. They will play alternatively, which means in the first chance ‘Ale’ will collect the stones, in second-chance ‘Bob’ will collect the stones. And always ‘Ale’ will start the game.

3. If any player is not able to take any stones then another player will win the game.

You are given an integer 'N'. You need to find the sum of squares of the first 'N' natural numbers.

For example:

If 'N' = 4. You need to return 1^2 + 2^2 + 3^2 + 4^2 = 30.

You have been given a Binary Tree of 'N' nodes where the nodes have integer values.

Your task is to find the largest number that could be formed by concatenating all its nodes values.

For example:

For the given binary tree:   

Output: 96553210    

Explanation: After concatenating all the numbers in the above binary tree this is the largest number that can be formed. 

Given an undirected graph of V vertices and E edges. Your task is to find all the bridges in the given undirected graph. A bridge in any graph is defined as an edge which, when removed, makes the graph disconnected (or more precisely, increases the number of connected components in the graph).

For Example :

If the given graph is :

Then the edge between 0 and 4 is the bridge because if the edge between 0 and 4 is removed, then there will be no path left to reach from 0 to 4.and makes the graph disconnected, and increases the number of connected components.

Note :

There are no self-loops(an edge connecting the vertex to itself) in the given graph.

There are no parallel edges i.e no two vertices are directly connected by more than 1 edge.