Mock interview Jan 30, 2019 - 10:00 PM - 11:47 PM - 1:06

Leetcode 979 Distribute coins between binary tree

//post order
leftMoves  = getMoves(left) // 1
rightMoves = getMoves(right) // -1
ownMoves = node.val === 0? -1 : node.val // wrong
totalMoves = Math.abs(leftMoves) + Math.abs(rightMoves) // each node will be visted once - //moves from each edge 
return ownMoves + leftMoves + rightMoves // definition of recursive function

Example 4:
      4 
   /-2 -1\
  0       0
  \ -1
  0 -1  - should be the coins needed to move - recursive function +, - 
  
total moves -> absolution

3 0 0 1 
1 2
-> coins move -> piggyback -> node value calculation first
take two steps:

for example: 

left child - math.abs(child.val - 1)
right child - math.abs(child.val - 1)
how many coins we need to move
determine the value of root node -> ?
  1 + 1 + new root value = root.val + left.val + right.val
new root.val 

The above steps can be in recursive function - post order traversal