Currently practicing: NeetCode Blind 75

**Insights**

- For tree problems, recursive DFS is cleanest to implement.

**Problems Solved**

find the difference in the count of letters in both numbers.

since there are only 26 letters, you can count in a single int array of 26.

index = char - 'a'

first right to left while multiplying.

Then second left to right while multiplying.

This can be done in a single array and one extra product variable

If an opening bracket is found, put the closing bracket in a stack.

If the closing bracket is found, pop and check for equality.