Day 16 : Maximum Level Sum

Easy

0/40

Average time to solve is 15m

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Asked in companies

Problem statement

Given a Binary Tree with integer nodes, your task is to find the maximum level sum among all the levels in the Binary Tree. The sum of any level in a tree is the sum of all the nodes present at that level.

Detailed explanation ( Input/output format, Notes, Images )

Input Format:

The first line will contain 'T', the number of test cases.

The only line of each test case contains elements in the level order form. The line consists of values of nodes separated by a single space. In case a node is null, we take -1 on its place.

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. 
The sequence will be put together in a single line separated by a single space. Hence, for the     above-depicted tree, the input will be given as:

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

Output Format:

For each test case, return a single integer denoting the maximum level sum.

The output for each test case is printed in a separate line.

Note:

You do not need to print anything, it has already been taken care of. Just implement the given function.

Constraints:

1 <= T <= 100
1 <= N <= 1000
-10^5  <= DATA <= 10^5 and DATA != -1    

Where ‘N’ is the number of nodes, 'DATA' is the value of nodes in the given tree.

Time limit: 1 sec

Sample Input 1:

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

Sample Output 1:

Explanation of Sample Output 1:

The Sum of all nodes of the 0th level is 4.

The Sum of all nodes of  the1st level is  2 + (-5) = -3.

The Sum of all nodes of the 2nd level is 1 + 3 +(-2) + 6 = 8.

Hence, the maximum level sum is 8.

Sample Input 2:

1         
1 2 3 4 5 -1 8 -1 -1 -1 -1 6 7 -1 -1 -1 -1

Sample Output 2:

Explanation of Sample Output 2:

Maximum sum is at level 2 i.e. 4 + 5 + 8 = 17.

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