Calculating the sum of each level in the tree

Question:


Given a binary tree with nodes containing integer values. Your algorithm should calculate the sum of values in each depth and returns sums.

Example:

          1
         /   \
       2     3
      /  \   /  \
    4   5 1    2

Output:  1, 5, 12

Answer

I don't remember where I saw this problem. If I remember I will update the labels.

I am still struggling with editing my layout. I would like to show the labels rather than the archive.
If you know how to do it, please, leave a comment. It will be a true win-win.

As the title indicates, it is a classic breast first search(BFS) problem. Using the BFS you can sum up the values and store in the output to return at the end of the problem.

Time complexity : $ (N)$
Space complexity:  $O(N)$

Here is the C++ source


UPDATE(2019-07-31): Solved the problem in python. I wrote the code quickly but got the test cases wrong. Took too long to find that bug after adding two print statements.


Practice statistics

7:00: to come up with an algorithm
13:00: to write up the code and test code (no bug)
07:00: to find the bug in the test code. (building the tree was wrong).

Total: 26:20

UPDATE(2022-06-14): solved again with no errors. Used python list as a queue.


04:32: for algorithm and pseudo code
08:18: to write up the code

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