A flow chart has steps 0 .. n-1; nexts[i] lists the steps you may go to directly after step i.
The arrows never form a loop. Return every route that starts at step 0 and ends at the last step
n - 1, each as the list of steps visited. Routes may be returned in any order.
Examples
Input: nexts = [[1, 2], [2], []]
Output: [[0, 1, 2], [0, 2]]
Input: nexts = [[]]
Output: [[0]]
Explanation: the start is already the last step.
Input: nexts = [[1], [], []]
Output: []
Explanation: step 2 cannot be reached.
Constraints
1 <= n <= 14, the graph has no cycles, no repeated arrows- The number of routes is at most a few thousand.
Goals
- Enumerate all paths in a directed acyclic graph with a path stack
- Understand why a DAG needs no visited set for simple paths