1)
Get average of all elements in binary search tree which are in range [low, high] inclusive.
6
/ \
4 8
/ \ / \
3 2 7 9
/
2

Input: [3, 10] => 6 because (42/7)
Input: [2, 5] => 3.5 because (14/4)

2)
123456789 = 100
Using standard integer arithmetic operators +, -, what are those different solutions you can find by inserting the operators between some digits?
EX)

• -1+2-3+4+5+6+78+9
• 123-45-67+89 # 100

Similar to https://leetcode.com/problems/expression-add-operators/

Good luck! Only managed to get a solution to the 1st one, second one walked through what I thought would be the solution and managed to only roughly implement it.