SDE - 1

You have been given an N*M matrix where there are 'N' rows and 'M' columns filled with '0s' and '1s'.

'1' means you can use the cell, and '0' means the cell is blocked. You can move in the 4 following directions from a particular position (i, j):

1. Left - (i, j-1)
2. Right - (i, j+1)
3. Up - (i-1, j)
4. Down - (i+1, j)

Now, for moving in the up and down directions, it costs you $1, and moving to the left and right directions are free of cost.

You have to calculate the minimum cost to reach (X, Y) from (0, 0) where 'X' is the row number and 'Y' is the column number of the destination cell. If it is impossible to reach the destination, print -1.

You are given an integer of array/list 'ARR' of length ‘N. You are supposed to return true if it is possible to construct at least one non-degenerate triangle using values of array/list as sides of the triangle, otherwise, return false.

You are given an array/list of ‘N’ integers. You are supposed to return the maximum sum of the subsequence with the constraint that no two elements are adjacent in the given array/list.

Note:

A subsequence of an array/list is obtained by deleting some number of elements (can be zero) from the array/list, leaving the remaining elements in their original order.

For a given binary tree, convert it to its sum tree. That is, replace every node data with sum of its immediate children, keeping leaf nodes 0. Finally, return its preorder.

For example:

The input for the tree depicted in the below image would be :

1
2 3
4 -1 5 6
-1 7 -1 -1 -1 -1
-1 -1

Explanation :

Level 1 :
The root node of the tree is 1

Level 2 :
Left child of 1 = 2
Right child of 1 = 3

Level 3 :
Left child of 2 = 4
Right child of 2 = null (-1)
Left child of 3 = 5
Right child of 3 = 6

Level 4 :
Left child of 4 = null (-1)
Right child of 4 = 7
Left child of 5 = null (-1)
Right child of 5 = null (-1)
Left child of 6 = null (-1)
Right child of 6 = null (-1)

Level 5 :
Left child of 7 = null (-1)
Right child of 7 = null (-1)

The first not-null node (of the previous level) is treated as the parent of the first two nodes of the current level. The second not-null node (of the previous level) is treated as the parent node for the next two nodes of the current level and so on.
The input ends when all nodes at the last level are null (-1).

Note :

The above format was just to provide clarity on how the input is formed for a given tree. 
 In the input, each value of the sequence will be present on a separate line.

Core concepts like deadlock, semaphore, memory management

Core concepts like indexing