Dfs

You are given the root of a binary tree containing digits from 0 to 9 only. Each root-to-leaf path in the tree represents a number. For example, the root-to-leaf path 1 -> 2 -> 3 represents the number 123. Return the total sum of all root-to-leaf numbers. Test cases are generated so that the answer will fit in a 32-bit integer. A leaf node is a node with no children.

Given a matrix mat[][] with r rows and c columns, where some cells are landmines (marked as 0) and others are safe to traverse. Your task is to find the shortest safe route from any cell in the leftmost column to any cell in the rightmost column of the mat. You cannot move diagonally, and you must avoid both the landmines and their adjacent cells (up, down, left, right), as they are also unsafe.