Software Engineer

Ninja loves playing with numbers. One day Alice gives him some numbers and asks him to find the Kth largest value among them.

Given an arithmetic expression ‘EXP’ containing integer values separated by any of the three operators ‘ + ’, ‘ - ’ and ‘ * ’. You need to place parentheses in the given expression such that the value of expression gets maximized. Your task is to return the maximum value obtained.

For Example:

If the Input Expression is 3*5+2, then the maximum value of ‘21’ can be obtained by placing the parentheses as 3*(5+2). So you need to return 21.

A minimum spanning tree is a subset of the edges of a connected, edge-weighted undirected graph that connects all the vertices without any cycles and with the minimum possible total edge weight.

A spanning tree’s weight is the sum of the weights of each edge in the spanning tree.

You have been given a connected undirected weighted graph having 'n' vertices, from 1 to 'n', and 'm' edges.

You are given an array 'edges' of size 'm', containing the details of the edges of the graph.

Each element of 'edges' contains three integers, the two vertices that are being connected and the weight of the edge.

Find the weight of the minimum spanning tree of the given graph.

Example :

Input: 'n' = 5, 'm' = 6
'edges' = [[1, 2, 6], [2, 3, 5], [3, 4, 4], [1, 4, 1], [1, 3, 2], [3, 5, 3]]

Output: 11

Explanation: The given graph is:

The minimum spanning tree of the graph is:

And its weight is 1 + 2 + 5 + 3 = 11.

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.

You have been given a binary tree of integers. You are supposed to find the left view of the binary tree. The left view of a binary tree is the set of all nodes that are visible when the binary tree is viewed from the left side.

Example:

The left view of the above binary tree is  {5, 7, 14, 25}.