Trees

Question 1

Vertical Order

Answer 1

1. two queue “q” to process the element to get the “col “for the element
2. Maintain map of column and lists use the col to get lsit and add value;
3. If left, add it q and add it col q with col - 1, min(min, col - 1)
4. for its col + 1 and max(max, col - 1)
5. Finally iterate from the min to max and get the list from the hashmap and add it to the result

Question 2

Sum of root to leaf node

Answer 2

1. recursive(root, sum)
2. sum += sum * 10 + root.val
3. recursive(left, sum) + recursive(right, sum)