Leetcode Problem 1466. Reorder Routes to Make All Paths Lead to the City Zero

Algorithm

1. Initialize a counter count to 0 to keep track of edges to be reversed.
2. Create an adjacency list adj to represent the graph, including both original and artificial edges.
3. Perform a DFS starting from node 0.
   • Define a recursive function dfs that takes the current node and its parent as arguments.
   • For each neighbor of the current node, if the neighbor is not the parent, increment count by the edge's value (1 for original, 0 for artificial) and recursively call dfs with the neighbor as the new node.
4. After the DFS completes, return the value of count.