Bottom view of a binary tree

This problem appeared on Daily Codings. But I took the problem statement from Geekforgeeks.

Given a Binary Tree, we need to print the bottom view from left to right. A node x is there in output if x is the bottommost node at its horizontal distance. The horizontal distance of the left child of a node x is equal to a horizontal distance of x minus 1, and that of a right child is the horizontal distance of x plus 1.

Examples:

                      20
                    /    \
                  8       22
                /   \      \
              5      3      25
                    / \      
                  10    14

For the above tree, the output should be 5, 10, 3, 14, 25.

If there are multiple bottom-most nodes for a horizontal distance from the root, then print the later one in the level traversal. For example, in the below diagram, 3 and 4 are both the bottom-most nodes at a horizontal distance of 0, we need to print 4.

                      20
                    /    \
                  8       22
                /   \    /   \
              5      3 4     25
                    / \      
                  10    14

For the above tree, the output should be 5 10 4 14 25.

Solutions: Look at from the bottom, all the leaf nodes must be included. There are some non-leaf node has to be included. Why non-leaf node? For second example, if you look from the bottom, you see 3 is visible…